4-F /ˌfɔːr ˈef/ noun, adjective
used in the US to describe someone who is not allowed to become a member of the US military forces because of physical, mental, or moral reasons

[TahlilGaran] Dictionary of Contemporary English ▲

I. F¹ , f /ef/ (plural F’s, f’s) noun

1. [uncountable and countable] the sixth letter of the English alphabet

2. [uncountable and countable] the fourth note in the musical scale¹(8) of C major or the musical key based on this note

3. [countable] a mark given to a student’s work to show that it is not good enough:
I got an F in chemistry.
⇒ f-word

[TahlilGaran] Dictionary of Contemporary English ▲

II. F²

1. the written abbreviation of Fahrenheit:
Water boils at 212° F.

2. the written abbreviation of female

3. the written abbreviation of false

[TahlilGaran] Dictionary of Contemporary English ▲

f. (also f British English)

1. the written abbreviation of forte, used in music to show that a part should be played or sung loudly

2. the written abbreviation of female

[TahlilGaran] Dictionary of Contemporary English ▲

F
Fail 
Failure 
False 
Female 
Fighter (US military aircraft designation; as in F-16) 
Flunked 
Full 
If

[TahlilGaran] Acronyms and Abbreviations Dictionary ▲

F0
Forum (or message board)

[TahlilGaran] Acronyms and Abbreviations Dictionary ▲

F
See: Free Out

[TahlilGaran] Acronyms and Abbreviations Dictionary ▲