Where a boy gets out of puff? (7)
I believe the answer is:
swindon
'where a' is the definition.
The definition suggests a singular noun which matches the answer.
'boy gets out of puff?' is the wordplay.
'boy' becomes 'son' (synonyms).
'gets' is an insertion indicator (gets can mean captures or absorbs).
'out of puff?' becomes 'wind' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'son' going around 'wind' is 'SWINDON'.
Can you help me to learn more?
(Other definitions for swindon that I've seen before include "English town" , "22 [WILTS] town" , "Large Wiltshire railway town" .)