Single, horrid taunt caused pain (10)
I believe the answer is:
unattached
'single' is the definition.
(not attached to a partner)
'horrid taunt caused pain' is the wordplay.
'horrid' indicates an anagram.
'caused pain' becomes 'ached'.
'taunt' anagrammed gives 'unatt'.
'unatt'+'ached'='UNATTACHED'
(Other definitions for unattached that I've seen before include "Not belonging" , "Not joined" , "independent" , "Single" , "Not married" .)