Top perspirer (7)
I believe the answer is:
sweater
This clue is a double definition.
'top' is the first definition.
(type of top or jumper)
'perspirer' is the second definition.
(someone who sweats or perspires)
(Other definitions for sweater that I've seen before include "Heavy jersey" , "Re waste: it's a garment" , "Woolly" , "Jumper (7)" , "Warm garment" .)