fatuous.adjective
vacuously, smugly, and unconsciously foolish; delusive; unreal
fatuously.adverb
fatuousness.nouns

fauna.noun
the animals of a given region or period considered as a whole. Compare flora
faunal.adjective

favor.noun
a gracious, friendly, or obliging act that is freely granted (do someone a favor);. friendly or favorable regard; approval or support (God had favor towards; looked with favor on the plan); advantage; benefit (sailed under favor of cloudless skies);a state of being held in such regard (a style currently in favor); something given as a token of love, affection, or remembrance; favoritism; a privilege or concession; a small decorative gift given to each guest at a party
favor, favored, favoring, favors.verbs
transitive verb senses.to perform a kindness or service for; oblige; to treat or regard with friendship, approval, or support; to be partial to; indulge a liking for (favors bright colors); to be or tend to be in support of; to make easier or more possible; facilitate (darkness favored their escape); to treat with care; be gentle with (favored a wounded leg); to resemble in appearance (she favors her father)
intransitive verb senses.to resemble another in appearance (she and her father favor)
in favor of.idiom; in support of; approving (we are in favor of his promotion to president; to the advantage of (the court decided in favor of the plaintiff; inscribed or made out to the benefit of (a cheque in favor of a charity)
favorer.noun
favoringly.adjective

favoritism.noun
the showing of special favor; partiality; the state or fact of being a favorite

feasible.adjective
capable of being done or carried out; possible; probable 
feasibility.noun

feeble.adjective
weak; not strong; without force or effectiveness; easily broken; frail
feebly.adverb
in a feeble manner
feeble minded.adjective
mentally weak or deficient; subnormal in intelligence; irresolute

feel.verb
inflected form(s).felt, felt, feeling
transitive senses-to have one's sensibilities markedly affected by; to be conscious of an inward impression, state of mind, or physical condition; to have a marked sentiment or opinion (feels strongly about it) 
feeling.noun
susceptibility to impression; sensitivity (the remark hurt her feelings) 
as an.adjective-feeling
sentient, sensitive; easily moved emotionally; expressing emotion or sensitivity 
feelingness.noun
feelingly.adverb

feign, feigned, feigning, feigns.transitive verbs
well turned words designed to fabricate falsities; to give a false appearance of (feign sleep); to represent falsely; pretend to (feign authorship of a novel); to imitate so as to deceive (feign another's voice); to fabricate (feigned an impression) upon them)
synonyms.pretend, assume, affect, simulate, fake, counterfeit

felicitous.adjective.(pronunciation 'fell is it us')
very well suited or expressed; apt.(a felicitous remark); pleasant; delightful 
felicitousness.noun
felicitously.adverb
synonym.fit

fellowship.noun
the condition of sharing similar interests, ideals, or experiences, as by reason of profession, religion, or nationality; the companionship of individuals in a congenial atmosphere and on equal terms; a close association of friends or equals sharing similar interests; friendship; comradeship

fend, fended, fending, fends.verbs
transitive senses.fend off – to ward off; fend for oneself – to get along without the help of others (fend off the cold); like a fender which fends off or protects something else
intransitive senses.to make an effort to resist (fend against the cold); to attempt to manage without assistance (the children had to fend for themselves while their parents worked)

fermion.noun.(quantum mechanics)
a fundamental.particle of matter of one half integral spin; electrons, protons and neutrons are fermions; a fermion cannot occupy the same quantum state because 2 fermions in a system would have their wave functions altered, or to put it another way, not more than one in a set of identical particles may occupy a particular quantum state; fermions make up matter and bosons.comprise a particle's forces.

ferocious.adjective
extremely savage; fierce; marked by unrelenting intensity; extreme
ferociously.adverb
ferociousness.noun

ferritin.noun
an iron containing protein complex, found principally in the intestinal mucosa, spleen, and liver, that functions as the primary form of iron storage in the body

fervor.noun
intensity of feeling or expression; intense heat; implies a warm and steady emotion (read the poem aloud with great fervor)
fervency.noun
intense devotion
fervent.adjective
great warmth of feeling; intense devotion or earnestness; intense; ardent
synonyms.passion,-passionate

fickle.adjective
characterized by erratic changeableness or instability, especially with regard to affections or attachments; capricious
fickleness.noun
fickly.adverb

form.noun
the shape and structure of an object; the body or outward appearance of a person or an animal considered separately from the face or head; figure; the essence of something (was the form of the letter kindly?); the mode in which a thing exists, acts, or manifests itself; kind (a form of animal life; a form of speaking); a ceremony; a formula; a document with blanks for the insertion of details or information (application forms); manners or conduct as governed by etiquette, decorum, or custom; behavior according to a person's unique expression); proven ability to perform (a musician at the top of her form); a mold for the setting of concrete; a linguistic form
form, formed, forming, forms.verbs
transitive use.to give form to; shape (form clay into figures); to develop in the mind; conceive.(form an opinion); to shape or mold (dough, for example) into a particular form
intransitive use.to become formed or shaped; to come into being by taking form; arise; to assume a specified form, shape, or pattern
formability.noun
formable.adjective

formation.noun
the act or process of forming something or of taking form; something formed (beautiful cloud formations); the manner or style in which something is formed; structure (the distinctive formation of the human eye) 
formational.adjective

formal.adjective
relating to or involving outward form or structure; being or relating to essential form or constitution (a formal principle); following or being in accord with accepted forms, conventions, or regulations (had little formal education; went to a formal party); carried out, or done in proper or regular form: a formal complaint; a formal document); characterized by strict or meticulous observation of forms; methodical (very formal in their business transactions); stiffly ceremonious (a formal manner; a formal greeting; a formal bow to the monarch)
formal.noun
something, such as a gown or social affair, that is formal in nature (a formal dress; a formal function)
formally.adverb
formalness.noun

formality.noun,.plural.formalities
the quality or condition of being formal; rigorous or ceremonious adherence to established forms, rules, or customs; an established form, rule, or custom, especially one followed merely for the sake of procedure or decorum

figurehead.noun
a person given a position of nominal leadership but having no actual authority; a carved figure on the prow of a ship

feudal
relating to lands held in fee or to the holding of such lands
feudalism.noun
a political and economic system of Europe from the 9th to about the 15th century, based on the holding of all land in fief or fee and the resulting relation of lord to vassal and characterized by homage, legal and military service of tenants, and forfeiture; a political, economic, or social order resembling this medieval system
feudalist.noun
feudalistic.adjective

forbid, forbade, forbidden, forbidding, forbids.transitive verbs
to command someone not to do something (I forbid you to go); to command against the doing or use of (something); prohibit.(forbid smoking on buses); to have the effect of preventing; preclude.(discretion forbids a reply)
forbiddance, forbidder.nouns

forbidding.adjective
tending or threatening to impede progress (forbidding rapids); unpleasant; disagreeable (a forbidding scowl) having a menacing.aspect.(forbidding thunderclouds
forbiddingly.adverb