| | fid | | fully involved dad |
| | fids | | fully involved dads |
| | FIFA | | Fédération Internationale de Football Association |
| | FIFO | | first in , first out |
| | FIFO | | First in, first out |
| | FIIOOH | | Forget It I'm Out of Here |
| | FIO | | figure it out |
| | FIOFY | | figure it out for yourself |
| | fish | | First In Still Here |
| | fish | | First in, still here |
| | fish | | Forget It I'm Staying Here |
| | fitb | | fill in the blank |
| | fitb | | Fill In The Blanks |
| | fka | | formerly known as |
| | fka | | frequently known as |
| | fklw | | finders keepers, losers weepers |
| | FLA | | Four Letter Acronym |
| | FLA | | Four-letter acronym |
| | FLCH | | Feels Like Coming Home |
| | FLEA | | Four Letter Extended Acronym |
| | FLOPS | | floating point operations |
| | FLOPS | | Floating Point Operations per Second |
| | FLOPTICAL | | FLOppy oPTICAL disk/drive |
| | FLOTUS | | First Lady Of The United States |
| | FLW | | Famous Last Words |
| | fmao | | freezing my ass of |
| | FMCG | | Fast Moving Consumer Goods |
| | fmdidgad | | frankly my dear, I don't give a damn |
| | fmea | | failure mode effects analysis |
| | fmea | | find me an easy answer |
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