Penny is out in the wood (7)
I believe the answer is:
spinney
'wood' is the definition.
(I have seen 'little wood' mean 'spinney' so perhaps 'wood' could also mean 'spinney')
'penny is out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'penny'+'is'='pennyis'
'pennyis' anagrammed gives 'SPINNEY'.
'in the' acts as a link.
(Other definitions for spinney that I've seen before include "little wood" , "Copse of trees" , "Small clump of trees" , "Small area of trees" , "Small wood with undergrowth" .)