Splendid, splendid book (6)

I believe the answer is:

superb

'splendid' is the definition.
(thesaurus)

'splendid book' is the wordplay.
'splendid' becomes 'super' (I've seen this before).
'book' becomes 'b'.
'super'+'b'='SUPERB'

(Other definitions for superb that I've seen before include "First-rate" , "First class" , "Splendid, brilliant" , "Wonderful, really great" , "Brilliant, fantastic" .)

I've seen this clue in The Times.

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