Warm heart (mostly) and face (7)
I believe the answer is:
cordial
'warm' is the definition.
(similar in meaning)
'heart mostly and face' is the wordplay.
'heart' becomes 'core' (synonyms).
'mostly' means to remove the last letter (most but not all of the word).
'and' says to put letters next to each other.
'face' becomes 'dial' (face of a clock).
'core' with its final letter removed is 'cor'.
'cor'+'dial'='CORDIAL'
(Other definitions for cordial that I've seen before include "stimulating drink" , "Hearty - drink" , "Pleasant - soft drink" , "Friendly; fruit drink" , "drink with a fruity flavour" .)