Forest dweller, dull chap by all accounts (4)
I believe the answer is:
boar
'forest dweller' is the definition.
(boars live in forests)
'dull chap by all accounts' is the wordplay.
'dull chap' becomes 'bore' (boring person).
'by all accounts' shows a homophone (sound like) ('by all accounts' can mean 'we hear').
'bore' sounds like 'BOAR'.
(Other definitions for boar that I've seen before include "A wild male pig" , "Male swine" , "Sow's mate" , "Wild pig sounds tedious" , "Uncastrated male hog" .)