Relax without father's meal (6)
I believe the answer is:
repast
'meal' is the definition.
(repast can mean a meal)
'relax without father's' is the wordplay.
'relax' becomes 'ret' (I can't justify this - if you can you should believe this answer much more).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'father's' becomes 'pa's' (pa can mean dad or father).
'ret' going around 'pas' is 'REPAST'.
Can you help me to learn more?
(Other definitions for repast that I've seen before include "lunch?" , "Feast, meal" , "A meal concerning time gone by" , "Banquet" , "Something to eat" .)