Robot with head of rubber, heart of foil and rear of lead (7)
I believe the answer is:
android
'robot' is the definition.
(android is a kind of robot)
'with head of rubber heart of foil and rear of lead' is the wordplay.
'with' becomes 'and'.
'head of' indicates taking the first letters.
'heart of' means to look at the middle letters.
'and' says to put letters next to each other.
'rear of' indicates one should take the final letters.
The middle of 'foil' is 'oi'.
The first letter of 'rubber' is 'r'.
The last letter of 'lead' is 'd'.
'and'+'r'+'oi'+'d'='ANDROID'
(Other definitions for android that I've seen before include "Robot resembling human being" , "Human-type robot" , "artificial being" , "Being not exactly human" , "Automaton resembling a human" .)