Stimulate a furtive look, we gather (5)
I believe the answer is:
pique
'stimulate' is the definition.
(I've seen this in another clue)
'a furtive look we gather' is the wordplay.
'a furtive look' becomes 'peek' (I've seen this before).
'we gather' indicates a 'sounds like' (homophone) clue (gather can mean to hear).
'peek' sounds like 'PIQUE'.
(Other definitions for pique that I've seen before include "Animosity" , "Slight reaction" , "Angry resentment" , "Irritation, resentment" , "Resentment; hurt pride" .)