Scarlet collars new cat relinquished (9)
I believe the answer is:
renounced
'relinquished' is the definition.
('renounce' can be a synonym of 'relinquish')
'scarlet collars new cat' is the wordplay.
'scarlet' becomes 'red' (synonyms).
'collars' indicates putting letters inside (to collar can mean to apprehend or capture).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'cat' becomes 'ounce' (ounce can mean a snow leopard).
'n'+'ounce'='nounce'
'red' placed around 'nounce' is 'RENOUNCED'.
(Another definition for renounced that I've seen is " Gave up".)