By and large this garment's unfinished (7)
I believe the answer is:
overall
'by and large' is the definition.
(thesaurus)
'this garment's unfinished' is the wordplay.
'this garment' becomes 'overalls' (I have seen 'Protective garment ' mean 'overalls' so perhaps 'garment' could also mean 'overalls').
'unfinished' means to remove the last letter.
'overalls' with its last letter taken off is 'OVERALL'.
(Other definitions for overall that I've seen before include "Protective outer garment" , "Comprehensive - protective garment" , "All over in general way" , "On the whole - protective garment" , "Supreme - general - protective garment" .)