Some touching expression of pain (4)
I believe the answer is:
ouch
'expression of pain' is the definition.
(I've seen this before)
'some touching' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'OUCH' can be found hidden inside 'touching'.
(Other definitions for ouch that I've seen before include "Shout of pain" , "Pained expression" , "Expression of pain" , "Ruby, perhaps once in it" , "brooch?" .)