Complete textbook, superb (7)
I believe the answer is:
perfect
I believe this is a triple definition!
'complete' is the first definition.
('perfect' can be similar in meaning to 'complete')
'textbook' is the second definition.
(I've seen this before)
'superb' is the third definition.
(thesaurus)
(Other definitions for perfect that I've seen before include "Mature" , "Past tense; ideal" , "Exemplary" , "Make right" , "Faultless" .)