Encounters set me off (5)
I believe the answer is:
'encounters' is the definition.
(I know this)
'set me off' is the wordplay.
'off' indicates an anagram.
'setme' anagrammed gives 'MEETS'.
(Other definitions for meets that I've seen before include "Joins with" , "Makes contact with" , "Hunts" , "Effectively copes with" , "Encounters or suffices" .)