Pack run in the morning (3)
I believe the answer is:
ram
'pack' is the definition.
('ram' can be a synonym of 'pack')
'run in the morning' is the wordplay.
'run' becomes 'r' (cricket abbreviation).
'in the morning' becomes 'am' (**).
'r'+'am'='RAM'
(Other definitions for ram that I've seen before include "Male animal; stuff" , "Strike violently" , "man with many partners?" , "Male sheep - bash into it" , "Crash into, maybe for battering" .)