May be tempted, perhaps unusually, to eat fourth toffee (4)
I believe the answer is:
fate
'may be tempted' is the definition.
I can't tell whether this defines the answer.
'unusually to eat fourth toffee' is the wordplay.
'unusually' is an anagram indicator.
'fourth toffee' becomes 'f' (4th letter of 'toffee').
'eat'+'f'='eatf'
'eatf' is an anagram of 'FATE'.
'perhaps' is the link.
Can you help me to learn more?
(Other definitions for fate that I've seen before include "Clotho, Lachesis or Atropos" , "Destiny, kismet" , "What must be" , "Fortune" , "Predetermined end" .)