Detestable swear-word employed by student a little (9)
I believe the answer is:
loathsome
'detestable' is the definition.
(I've seen this before)
'swear-word employed by student a little' is the wordplay.
'swear-word' becomes 'oath' (I've seen this before).
'employed by' says to put letters next to each other.
'student' becomes 'l' (as in L-plates for learner drivers).
'a little' becomes 'some' (I've seen this before).
'oath' after 'l' is 'loath'.
'loath'+'some'='LOATHSOME'
(Other definitions for loathsome that I've seen before include "gross" , "Hateful" , "Repulsive" , "Detestable" , "Disgusting, nauseating" .)