The majority of (4)
I believe the answer is:
most
'the majority of' is the definition.
(the majority of something means most of it)
This is the entire clue.
(Other definitions for most that I've seen before include "Almost all" , "In the highest degree" , "Nearly all, majority" , "Extremely, very" , "Kind of commercial pact where two countries agree to treat each other as well as any other" .)