Supply ecstasy and crack (5)
I believe the answer is:
equip
'supply' is the definition.
(I know that equip is a type of supply)
'ecstasy and crack' is the wordplay.
'ecstasy' becomes 'E' (informal term for the drug).
'and' is a charade indicator (letters next to each other).
'crack' becomes 'quip' (both can mean a joke).
'e'+'quip'='EQUIP'
(Other definitions for equip that I've seen before include "Fit out, supply" , "Provide with items (for particular task)" , "Sally" , "Outfit" , "Provide with kit" .)