Grab fruit, two packs a penny (6)
I believe the answer is:
scrump
'grab fruit' is the definition.
(scrumping is stealing fruit)
'two packs a penny' is the wordplay.
'two packs' becomes 'scrum' (a rugby scrum is made up of a pack from each team).
'a penny' becomes 'p' (short for pence).
'scrum'+'p'='SCRUMP'
(Other definitions for scrump that I've seen before include "Nick apples" , "theft" , "Nick in garden" , "steal from farmer" , "Steal apples from trees" .)