Father has to avail himself of a temporary rest (5)
I believe the answer is:
pause
'rest' is the definition.
(I know that rest is a kind of pause)
'father has to avail' is the wordplay.
'father' becomes 'pa' (pa can mean dad or father).
'has' says to put letters next to each other.
'to avail' becomes 'use' (I've seen this before).
'pa'+'use'='PAUSE'
'himself of a temporary' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for pause that I've seen before include "Take a break" , "Stoppage" , "Kick" , "Temporary inactivity" , "Wait" .)