Crossword Genius

Former partner, hammered, unravelled (9)

Ross

I believe the answer is:

expounded

I'm a little stuck... Click here to teach me more about this clue!

'unravelled' is the definition.
Although both the answer and definition are past participle verbs, I don't see how one could define the other.

'former partner hammered' is the wordplay.
'former partner' becomes 'ex' (an ex-partner).
'hammered' becomes 'pounded' (I can't explain this - if you can you should believe this answer much more).
'ex'+'pounded'='EXPOUNDED'

Can you help me to learn more?

(Other definitions for expounded that I've seen before include "Explained" , "made clear" , "commented on" .)

I've seen this clue in The Independent.
Want a hint initially instead of a full solution? Install my app