FIST
FIST is chiefly used in defense and military contexts to label advanced soldier technologies, fire‑support units, or specialized fleet teams, and it also appears in technical service job titles.
Governmental
Fire Support Team
Fleet Imagery Support Terminal
Fleet Initial Strike Team
File, Inform, Settle, or Trial
Fingerprinting Insures Safe Tots
Free Individual Self-defence Training
Fugitive Investigative Strike Team
Facilities, Instructions, Standards, and Techniques
Fleet Intelligence Support Team