Can family visit? (4-2)
I believe the answer is:
look-in
'visit?' is the definition.
(I have seen 'short visit' mean 'look in' so perhaps 'visit' could also mean 'look in')
'can family' is the wordplay.
'can' becomes 'loo' (both can informally mean toilet).
'family' becomes 'kin' (synonyms).
'loo'+'kin'='LOOK-IN'
(Other definitions for look-in that I've seen before include "Make a short visit of visual sort?" , "Chance of success" , "Watch TV (colloq.)" .)