Grassy area in a clearing (3)
I believe the answer is:
lea
'grassy area' is the definition.
(lea can mean a meadow or field)
'in a clearing' is the wordplay.
'in' indicates a hidden word.
'LEA' is hidden in the letters of 'clearing'.
(Other definitions for lea that I've seen before include "Open area of grassy or arable land" , "area of grassland" , "'The lowing herd wind slowly o'er the . . .'" , "Open country" , "grazing area" .)