Article like this enthrals learner as well (4)
I believe the answer is:
also
'as well' is the definition.
('also' can be a synonym of 'as well')
'article like this enthrals learner' is the wordplay.
'article' becomes 'a' (indefinite article).
'like this' becomes 'so'.
'enthrals' is an insertion indicator.
'learner' becomes 'l'.
'a'+'so'='aso'
'aso' placed around 'l' is 'ALSO'.
(Other definitions for also that I've seen before include "To boot" , "into the bargain" , "Old" , "Plus" , "an indication of more to come" .)