The crew dined, we hear (5)
I believe the answer is:
eight
'the crew' is the definition.
(an eight-person rowing team)
'dined we hear' is the wordplay.
'dined' becomes 'ate' (I've seen this in another clue).
'we hear' shows a homophone (sound like).
'ate' is a homophone of 'EIGHT'.
(Other definitions for eight that I've seen before include "Chaps having row" , "Number in a Boat Race crew" , "Perfect cube" , "Team involved in row" , "Where arrogance is needed" .)