Teeming area with wood (5)
I believe the answer is:
awash
'teeming' is the definition.
'area with wood' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'with' becomes 'w' (abbreviation).
'wood' becomes 'ash' (I've seen this before).
'a'+'w'+'ash'='AWASH'
(Other definitions for awash that I've seen before include "Flooded; about to sink" , "becomes flooded" , "Overflowing" , "Covered by water - sounds cleansing" , "Doused in water" .)