Adhesive, tacky (6)
I believe the answer is:
sticky
I believe this is a double definition.
'adhesive' is the first definition.
(similar in meaning)
'tacky' is the second definition.
(I've seen this before)
(Other definitions for sticky that I've seen before include "Glutinous, gooey" , "Damp with sweat" , "Warm and humid" , "Adhesive; awkward" , "Close" .)