Early meeting might end firm (5,9)
I believe the answer is:
power breakfast
'early meeting' is the definition.
(I've seen this before)
'might end firm' is the wordplay.
I cannot quite understand how this works, but
'might' could be 'power' (being mighty) and 'power' is present in the answer.
'end' could be 'break' (breaking is a kind of ending) and 'break' is present in the answer.
'firm' could be 'fast' (synonyms) and 'fast' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for power breakfast that I've seen before include "summit early?" , "Influence, by chance, quick early business meeting" .)