Lousy clubs introducing pack activity? (6)
I believe the answer is:
crummy
'lousy' is the definition.
'clubs introducing pack activity?' is the wordplay.
'clubs' becomes 'c' (abbreviation used in card games such as bridge).
'introducing' says to put letters next to each other.
'pack activity?' becomes 'rummy' (a 'pack activity' could mean a card game).
'c'+'rummy'='CRUMMY'
(Other definitions for crummy that I've seen before include "Dirty and inferior" , "Poor" , "Very bad" , "Inferior (colloq.)" .)