Touchy, exhibiting a pained expression (4)
I believe the answer is:
ouch
'a pained expression' is the definition.
(I've seen this in another clue)
'touchy exhibiting' is the wordplay.
'exhibiting' indicates a hidden word (I've seen 'exhibits' mean this).
'OUCH' can be found hidden inside 'touchy'.
(Other definitions for ouch that I've seen before include "Pained exclamation" , "Pained cry" , "that hurts!" , "brooch?" , "that's painful" .)