Dull band including student (5)
I believe the answer is:
bland
'dull' is the definition.
('bland' can be similar in meaning to 'dull')
'band including student' is the wordplay.
'including' indicates putting letters inside.
'student' becomes 'l'.
'band' enclosing 'l' is 'BLAND'.
(Other definitions for bland that I've seen before include "Mild; dull" , "without distinctive characteristics" , "Flavourless" , "Boring" , "Without flavour" .)