Even half of it can possibly hurt! (5)
I believe the answer is:
truth
'even half' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'it can possibly hurt' is the wordplay.
I cannot really understand how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is located in the answer.
an anagram of 'hurt' is 'ruth' which is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
Can you help me to learn more?
(Other definitions for truth that I've seen before include "known facts" , "real story" , "Veracity; established fact" , "Actuality" , "Candour" .)