Amorous heart embraces sex appeal returning (6)
I believe the answer is:
erotic
'amorous' is the definition.
(I've seen this before)
'heart embraces sex appeal returning' is the wordplay.
'heart' becomes 'core' (synonyms).
'embraces' indicates putting letters inside.
'sex appeal' becomes 'it'.
'returning' says the letters should be written in reverse.
'core' placed around 'it' is 'citore'.
'citore' back-to-front is 'EROTIC'.
(Other definitions for erotic that I've seen before include "Sexy" , "Relating to sexual desire" , "Dirty - blue" , "Relating to sexual pleasure" , "Calculated to arouse sexual thoughts" .)