Bulldog booster (3)
I believe the answer is:
eli
'bulldog booster' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for eli that I've seen before include "High priest in the Book of Samuel" , "Biblical teacher of Samuel" , "Old Testament high priest" , "OT high priest" , "- Whitney invented the cotton gin in seventeen ninety three" .)