Animal caught in field, hiding in grass (7)
I believe the answer is:
polecat
'animal' is the definition.
(thesaurus)
'caught in field hiding in grass' is the wordplay.
'caught' becomes 'c' (cricket abbreviation**).
'in' means one lot of letters goes inside another.
'field' becomes 'lea' (I've seen this before).
'hiding in' indicates putting letters inside.
'grass' becomes 'pot' (cannabis).
'c' going into 'lea' is 'leca'.
'leca' going within 'pot' is 'POLECAT'.
(Other definitions for polecat that I've seen before include "Beast related to weasel" , "weaselly creature" , "American skunk" , "Kind of weasel, called skunk in America" , "Smelly American mammal" .)