Man first to abominate large check trousers (5)
I believe the answer is:
valet
'man' is the definition.
(I know that man can be written as valet)
'first to abominate large check trousers' is the wordplay.
'first to' indicates taking the first letters.
'check' becomes 'vet' (I've seen this in other clues).
'trousers' is an insertion indicator (to trouser can mean to steal or take).
The first letters of 'abominate large' is 'al'.
'al' placed into 'vet' is 'VALET'.
(Other definitions for valet that I've seen before include "Man's manservant" , "Male servant" , "'No man is a hero to his . . . . .'" , "Gentleman%u2019s gentleman" , "Man's servant" .)