Compatible with pet (3)
I believe the answer is:
pat
'pet' is the definition.
(thesaurus)
'compatible with' is the wordplay.
'with' says the answer is hidden in the clue.
'PAT' can be found hidden inside 'compatible'.
(Other definitions for pat that I've seen before include "Girl" , "Slick; dab" , "well-rehearsed" , "Some butter, maybe" , "Conveniently; light touch" .)