Cold-blooded animal (7)
'cold-blooded animal' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for reptile that I've seen before include "Malignant creature" , "Snake or crocodile, say" , "Serpent" , "loathsome type" , "Cold-blooded creature" .)
(Other definitions for inhuman that I've seen before include "Unfeelingly cruel" , "Animal" , "Savage, brutal" , "diabolical ..." , "Cruel, bestial" .)