With idiot removed, class always seems bright! (6)
I believe the answer is:
clever
'bright' is the definition.
(bright can mean clever or intelligent)
'with idiot removed class always' is the wordplay.
'with' says to put letters next to each other.
'idiot' becomes 'ass' (both can mean a stupid person).
'removed' indicates named letters should be taken away.
'always' becomes 'ever' (synonyms).
'class' with 'ass' taken out is 'cl'.
'cl'+'ever' is 'CLEVER'.
'seems' acts as a link.
(Other definitions for clever that I've seen before include "Mentally or physically skilful" , "Intelligent - skilful" , "Adroit, ingenious" , "Smar and canny" , "Bright, quick-witted, intelligent" .)