Keen listener comprehending good English (5)
I believe the answer is:
eager
'keen' is the definition.
(thesaurus)
'listener comprehending good english' is the wordplay.
'listener' becomes 'ear' (I've seen this before).
'comprehending' is an insertion indicator (comprehend can mean include or contain).
'good' becomes 'g' (abbreviation).
'english' becomes 'e' (abbreviation).
'g'+'e'='ge'
'ear' placed around 'ge' is 'EAGER'.
(Other definitions for eager that I've seen before include "Agree (anag.)" , "Showing keen interest" , "Like some beavers" , "willing" , "Keenly interested" .)