Chance of a rest (5)
I believe the answer is:
break
This clue is a double definition.
'chance' is the first definition.
(thesaurus)
'a rest' is the second definition.
(I've seen this before)
'of' is the link.
(Other definitions for break that I've seen before include "Fracture; holiday" , "Baker (anag.)" , "interval between lessons" , "Short holiday" , "Interruption" .)