Studies English? Foolish (5)

I believe the answer is:

dense

'foolish' is the definition.
(thesaurus)

'studies english?' is the wordplay.
'studies' becomes 'dens' (I've seen this before).
'english?' becomes 'e' (abbreviation).
'dens'+'e'='DENSE'

(Other definitions for dense that I've seen before include "Slow-witted" , "Close-packed" , "Maybe bovine" , "Close knit" , "Close - compact - stupid" .)

I've seen this clue in The Telegraph.

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