Rush meal, start to repent (4)
I believe the answer is:
tear
'rush' is the definition.
(tearing is a kind of rushing)
'meal start to repent' is the wordplay.
'meal' becomes 'tea' (tea is a kind of meal).
'start to' suggests taking the first letters.
The initial letter of 'repent' is 'r'.
'tea'+'r'='TEAR'
(Other definitions for tear that I've seen before include "Move quickly; pull apart" , "Lachrymal fluid" , "speed" , "Drop secreted by the lacrimal glands" , "A rip and a sign of sadness" .)