Has to renew vows (5)
I believe the answer is:
oaths
'vows' is the definition.
('oath' can be a synonym of 'vow')
'has to renew' is the wordplay.
'renew' indicates an anagram (I've seen 'renews' mean this).
'has'+'to'='hasto'
'hasto' anagrammed gives 'OATHS'.
(Other definitions for oaths that I've seen before include "Profane expressions" , "Swear words" , "Cursing" , "Curses - words of honour?" , "Solemn promises or curses" .)