Class's leaders, always brainy (6)

I believe the answer is:

clever

I'm a little stuck... Click here to teach me more about this clue!

'brainy' is the definition.
(I've seen this before)

'class's leaders always' is the wordplay.
'class's leaders' becomes 'cl' (this could be a standard abbreviation of which I'm unaware).
'always' becomes 'ever' (synonyms).
'cl'+'ever'='CLEVER'

Can you help me to learn more?

(Other definitions for clever that I've seen before include "Highly intelligent" , "Quick and intelligent" , "Quick at learning, bright" , "Smart, adroit" , "Smar and canny" .)

I've seen this clue in The Daily Express.

Want a hint initially instead of a full solution? Install my app