Contract permitting relaxation, at length (5)
I believe the answer is:
lease
'contract' is the definition.
(leasing is a kind of contracting)
'relaxation at length' is the wordplay.
'relaxation' becomes 'ease' (synonyms).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'length' becomes 'l' (abbreviation in geometry).
'ease' put after 'l' is 'LEASE'.
'permitting' is the link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for lease that I've seen before include "Contract for, say, use of building" , "Term of a rental contract" , "Renting contract" , "Contract allowing use of a property" , "Rent (a property)" .)