Not quite all (4)
I believe the answer is:
most
'not quite all' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for most that I've seen before include "Kind of commercial pact where two countries agree to treat each other as well as any other" , "Extremely, very" , "Greatest in amount or degree" , "Nearly all, majority" , "In the highest degree" .)