Wild foxes eat raccoons and lizards first (5)
I believe the answer is:
feral
'wild' is the definition.
(similar in meaning)
'foxes eat raccoons and lizards first' is the wordplay.
'first' indicates taking the first letters.
The initial letters of 'foxes eat raccoons and lizards' is 'FERAL'.
(Other definitions for feral that I've seen before include "Wild and menacing" , "Wild (though once tame)" , "Flare up, going wild" , "Flare up, being fierce" , "Wild but formerly tame" .)