Unpleasantly sticky (6)
I believe the answer is:
clammy
'unpleasantly sticky' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for clammy that I've seen before include "Wet and sticky" , "Stewing" , "Unpleasantly sticky and moist" , "(Of weather) sticky" , "Moist and adhesive" .)