Obsession that keeps one going to matches? (9)
I believe the answer is:
pyromania
'one going to matches?' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'obsession that' is the wordplay.
I cannot really understand how this works, but
'obsession' could be 'mania' (I've seen this before) and 'mania' is found within the answer.
The remaining letters 'pyro' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'keeps' acts as a link.
(Other definitions for pyromania that I've seen before include "setting of conflagration" , "criminal tendency" , "Fire-raising impulse" , "Flaming madness!" , "Pay Marion (anag.)" .)