Pine touched by part of saw: it may need drilling (9)
I believe the answer is:
toothache
'it may need drilling' is the definition.
The definition suggests a singular noun which matches the answer.
'pine touched by part of saw' is the wordplay.
'pine' becomes 'ache' (synonyms).
'touched by' is a charade indicator (letters next to each other).
'part of saw' becomes 'tooth' ('tooth' is part of 'saw').
'ache' put after 'tooth' is 'TOOTHACHE'.
Can you help me to learn more?
(Other definitions for toothache that I've seen before include "Dental problem" , "Dental pain" , "Odontalgia" , "Cause of sore mouth" , "Pain in the mouth" .)