Keep puffing, Puff? (6)
I believe the answer is:
dragon
'keep puffing' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'puff?' is the wordplay.
I cannot really see how this works, but
'puff?' could be 'drag' ('drag' can be a synonym of 'puff') and 'drag' is located in the answer.
The remaining letters 'on' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for dragon that I've seen before include "Legendary fire-breather" , "Mythical fire-breather" , "Monster - type of fly" , "Mythological creature is no grad" , "eg Puff, Fafner" .)