Expected to eat quietly, but jumped (6)
I believe the answer is:
hopped
'jumped' is the definition.
(hopping is a kind of jumping)
'expected to eat quietly' is the wordplay.
'expected' becomes 'hoped' ('hope' can be a synonym of 'expect').
'to eat' is an insertion indicator.
'quietly' becomes 'p' (p for piano and quiet).
'hoped' enclosing 'p' is 'HOPPED'.
'but' is the link.
(Other definitions for hopped that I've seen before include "Jumped lightly" , "Moved in jumps" , "Jumped on one leg" , "Jumped about on one foot" .)