Temptation to break a rule (4)
I believe the answer is:
lure
'temptation' is the definition.
(lure is a kind of temptation)
'break a rule' is the wordplay.
'break' indicates anagramming the letters.
'rule' with letters rearranged gives 'LURE'.
'to' is the link.
(Other definitions for lure that I've seen before include "It's used to attract fish" , "Attract with bait" , "Entice, bait" , "Tempt invoking rule" , "Enticement" .)