Covered in perspiration (6)
I believe the answer is:
sweaty
'covered in perspiration' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sweaty that I've seen before include "Given to perspiring, in moist state" , "affected by the heat" , "Covered in perspiration" , "Hot and perspiring" , "Damp with perspiration" .)