| A | B |
| fiasco | a complete failure |
| fickle | likely to change for no apparent reason |
| finesse | skill, delicacy in doing something |
| flagrant | extremely and deliberately conspicuous |
| frugal | thrifty or economical in the use of money |
| fluctuate | to change continually from one position to another |
| foible | a minor, often amusing, fault or weakness in character |
| formidable | arousing fear or admiration because of the unusal size of something involved |
| fortutitous | occurring by chance or accident |
| filch | to steal slyly, especially small things |
| flaunt | to show off in a conspicuous way |
| flout | to treat openly with scorn or contempt |
| forestall | to secure an advantage or prevent a loss by previous action |
| fulsome | excessive and offensive to good taste and obviously insincere |
| futile | incapable of producing the desired result; unsuccessful |