Fast

Fast (noun), high speed or velocity
Fast (noun, verb), to practice fasting, abstaining from food and/or water for a certain period of time

Acronyms and coded

Faceted Application of Subject Terminology, a thesaurus of subject headings
Facilitated Application Specification Techniques, a team-oriented approach for requirement gathering
FAST protocol, an adaptation of the FIX protocol, optimized for streaming
FAST TCP, a TCP congestion avoidance algorithm
FAST and later as Fast Search & Transfer, a Norwegian company focusing on data search technologies
Fatigue Avoidance Scheduling Tool, software to develop work schedules
Features from accelerated segment test, computer vision method for corner detection
Federation Against Software Theft, a UK organization that pursues those who illegally distribute software
Feedback arc set in Tournaments, a computational problem in graph theory
USENIX Conference on File and Storage Technologies

Faʻatuatua i le Atua Samoa ua Tasi, a political party in Samoa
Fixing America's Surface Transportation Act, passed by the United States Congress
Foreign-Deployed Advisory and Support Teams, a former program of the US Drug Enforcement Administration; see Drug Enforcement Administration § Special Response Teams
Free and Secure Trade, a Canada-United States and Mexico-United States program to facilitate faster cross border trade

Fleet Antiterrorism Security Team, a branch of the United States Marine Corps
Fuel And Sensor Tactical packs, a type of conformal fuel tank developed for the F-15
Future Assault Shell Technology helmet, a combat helmet of United States of America.

FAST (stroke) (Face, Arm, Speech, and Time), a mnemonic for the symptoms of a stroke
Farpoint Asteroid Search Team, an asteroid search team located at the Farpoint Observatory
Fast Auroral Snapshot Explorer, one in the series of NASA's Small Explorer spacecraft
Five-hundred-meter Aperture Spherical Telescope (五百米口径球面射电望远镜), a large single-dish radio telescope in Guizhou province, China
Fluorescence-activating and absorption-shifting tag, genetically-encoded protein tag used in molecular biology
Focused assessment with sonography for trauma, an ultrasound used to examine the abdomen of a trauma patient
Fourier amplitude sensitivity testing, a variance-based global sensitivity analysis method
Future Attribute Screening Technology

Fast Robinson (born 1994), English actor known professionally as Eddie-Joe Robinson