Early meeting might stop quickly (5,9)
I believe the answer is:
power breakfast
'early meeting' is the definition.
(I've seen this before)
'might stop quickly' is the wordplay.
'might' becomes 'power' (being mighty).
'stop' becomes 'break' (synonyms).
'quickly' becomes 'fast' (synonyms).
'power'+'break'+'fast'='POWER BREAKFAST'
(Other definitions for power breakfast that I've seen before include "Influence, by chance, quick early business meeting" , "summit early?" .)