It's clear dad's back with mum? (8)
I believe the answer is:
apparent
'it's clear' is the definition.
('apparent' can be a synonym of 'clear')
'dad's back with mum?' is the wordplay.
'dad' becomes 'pa' ('pa' can be a synonym of 'dad').
'back' shows that the letters should be reversed in order.
'with' means one lot of letters go next to another.
'mum?' becomes 'parent' (mum is a kind of parent).
'pa' in reverse letter order is 'ap'.
'ap'+'parent'='APPARENT'
(Other definitions for apparent that I've seen before include "Writ large" , "Seeming to be but not necessarily so" , "Seeming real or true" , "That may be seen" , "Obvious; seemingly true" .)