Cable-tie nuts to become chaste (8)
I believe the answer is:
celibate
'chaste' is the definition.
(similar in meaning)
'cable-tie nuts' is the wordplay.
'nuts' indicates an anagram (nuts can mean crazy).
'cable'+'tie'='cabletie'
'cabletie' anagrammed gives 'CELIBATE'.
'to become' is the link.
(Other definitions for celibate that I've seen before include "practising abstinence" , "Belie act of being voluntarily chaste" , "Remaining chaste for religious reasons." , "Continent" , "Living as a single person" .)