College student's constantly brilliant (6)
I believe the answer is:
clever
'brilliant' is the definition.
(I've seen this before)
'college student's constantly' is the wordplay.
'college' becomes 'c'.
'student' becomes 'L' (as in L-plates for learner drivers).
'constantly' becomes 'ever' (I've seen this in other clues).
'c'+'l'+'ever'='CLEVER'
(Other definitions for clever that I've seen before include "Smart or shrewd" , "Intelligent - skilful" , "Box ---, outwit someone" , "Sharp-witted, intelligent" , "Adroit, ingenious" .)