The burly test-playing bumpkin entering (8)
I believe the answer is:
thickset
'the burly' is the definition.
(thesaurus)
'test-playing bumpkin entering' is the wordplay.
'playing' indicates anagramming the letters.
'bumpkin' becomes 'hick' ('hick' can be a synonym of 'bumpkin').
'entering' means one lot of letters goes inside another.
'test' is an anagram of 'tset'.
'tset' placed around 'hick' is 'THICKSET'.
(Other definitions for thickset that I've seen before include "Heavily built" , "Closely planted" , "positioned close together" , "Concentrated" , "Solidly built; stocky" .)