| Term | Definition |
| fabricated | (adj) false; made up |
| facade | (noun) front; face; superficial appearance or mask |
| facilitate | (verb) to simplify; to bring about |
| fanatic | (adj/noun) overly enthusiastic (person) |
| fatal | (adj) deadly; destructive |
| fathom | (verb) to measure the depth of; to guage; to find the meaning of |
| fatigue | (noun) exhaustion; weariness; extreme tiredness |
| fauna | (noun) the animals of a specified time period |
| feasible | (adj) possible; plausible |
| feign | (verb) to pretend; to fake |
| feisty | (adj) easily drawn to quarrels; aggressive |
| felicitous | (adj) pleasing |
| ferocious | (adj) fierce; savage; violently cruel |
| fervent | (adj) intense; passionate |
| fiasco | (noun) disaster; total failure |
| fickle | (adj) inconstant; not loyal |
| fictitious | (adj) untrue; false |
| fidelity | (noun) loyalty; faithful devotion |
| finale | (noun) the ending |
| finicky | (adj) fussy; difficult to please |
| fission | (noun) process of breaking into parts |
| flagrant | (adj) offensive; outrageous; deliberately shocking |
| flaunt | (verb) to show off |
| flaw | (noun) an imperfection |
| flippant | (adj) disrespectful; frivolous; saucy |
| flounder | (verb) to stumble; to fall; to sink |
| flow | (verb) to move like a liquid; to pour out |
| fluctuate | (verb) to waver; to alternate; to move up and down |
| foreboding | (noun) sense of evil or doom is to come |
| forensic | (noun) relating to legal proceedings |
| foretell | (verb) to predict |
| formidable | (adj) awesome; difficult to achieve |
| forsake | (verb) to give up; to abandon; to withdraw from |
| foster | (verb) to cultivate; to nourish |
| foundation | (noun) establishment; basis |
| fragile | (adj) easily broken; delicate |
| frank | (adj) candid; open |
| fraudulent | (adj) dishonest; unethical |
| fraught | (adj) full of; filled with |
| frenzied | (adj) hectic; confused; agitated |
| frequent | (adj/noun) happening often; to go somewhere often |
| frivolity | (noun) the act of being carefree; self-indulgent |
| fund | (noun/verb) a supply; to offer money or support |
| fusion | (noun) process of combining into one |
| futile | (adj) lacking purpose |