Attentive to different part (4)
I believe the answer is:
rapt
'attentive' is the definition.
(similar in meaning)
'different part' is the wordplay.
'different' indicates an anagram (letters placed in a different order).
'part' with letters rearranged gives 'RAPT'.
'to' is the link.
(Other definitions for rapt that I've seen before include "Enraptured, entranced" , "Absorbed and enchanted" , "riveted" , "Ecstatic - engrossed" , "Completely absorbed" .)