- fixture: One who or that which is expected to remain permanently in its position.
- flag-officer: The captain of a flag-ship.
- flagrant: Openly scandalous.
- flamboyant: Characterized by extravagance and in general by want of good taste.
- flatulence: Accumulation of gas in the stomach and bowels.
- flection: The act of bending.
- fledgling: A young bird.
- flexible: Pliable.
- flimsy: Thin and weak.
- flippant: Having a light, pert, trifling disposition.
- floe: A collection of tabular masses of floating polar ice.
- flora: The aggregate of plants growing without cultivation in a district.
- floral: Pertaining to flowers.
- florid: Flushed with red.
- florist: A dealer in flowers.
- fluctuate: To pass backward and forward irregularly from one state or degree to another.
- fluctuation: Frequent irregular change back and forth from one state or degree to another.
- flue: A smoke-duct in a chimney.
- fluent: Having a ready or easy flow of words or ideas.
- fluential: Pertaining to streams.
- flux: A state of constant movement, change, or renewal.
- foggy: Obscure.
- foible: A personal weakness or failing.
- foist: To palm off.
- foliage: Any growth of leaves.
- folio: A sheet of paper folded once, or of a size adapted to folding once.
- folk-lore: The traditions, beliefs, and customs of the common people.
- fondle: To handle tenderly and lovingly.
- foolery: Folly.
- foot-note: A note of explanation or comment at the foot of a page or column.
- foppery: Dandyism.
- foppish: Characteristic of one who is unduly devoted to dress and the niceties of manners.
- forbearance: Patient endurance or toleration of offenses.
- forby: Besides.
- forcible: Violent.
- forebode: To be an omen or warning sign of, especially of evil.
- forecast: To predict.
- forecastle: That part of the upper deck of a ship forward of the after fore-shrouds.
- foreclose: To bar by judicial proceedings the equitable right of a mortgagor to redeem property.
- forecourt: A court opening directly from the street.
- forefather: An ancestor.
- forego: To deny oneself the pleasure or profit of.
- foreground: That part of a landscape or picture situated or represented as nearest the spectator.
- forehead: The upper part of the face, between the eyes and the hair.
- foreign: Belonging to, situated in, or derived from another country.
- foreigner: A citizen of a foreign country.
- forejudge: To judge of before hearing evidence.
- foreknowledge: Prescience.
- forepeak: The extreme forward part of a ship's hold, under the lowest deck.
- foreshore: That part of a shore uncovered at low tide.