When inside, is not able to get a game (7)
I believe the answer is:
canasta
'game' is the definition.
(canasta is a kind of game)
'when inside is not able to get a' is the wordplay.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'inside' means one lot of letters goes inside another.
'is not able to' becomes 'cant' (cannot).
'get' says to put letters next to each other.
'as' inserted into 'cant' is 'canast'.
'canast'+'a'='CANASTA'
(Other definitions for canasta that I've seen before include "Two-pack card game" , "Can a staff cook stomach game?" , "Card game -- as an act (anag)" , "Rummy-like card-game" , "this needs two packs" .)