Run away from heartless fool perhaps (6)
I believe the answer is:
desert
'run away from' is the definition.
(thesaurus)
'heartless fool perhaps' is the wordplay.
'heartless' says to hollow out the word (remove centre letters).
'fool perhaps' becomes 'dessert' (fool is a type of dessert).
'dessert' with its middle removed is 'DESERT'.
(Other definitions for desert that I've seen before include "unproductive area" , "Abandon; dry region" , "Leave - due" , "Abandon - barren region" , "Abandon in arid place" .)