Elgar's first movement and a student's sentimental (9)
I believe the answer is:
emotional
'sentimental' is the definition.
(similar in meaning)
'elgar's first movement and a student's' is the wordplay.
'elgar's first' becomes 'e' (lst letter of 'elgar').
'movement' becomes 'motion' (synonyms).
'and' says to put letters next to each other.
'student' becomes 'l' (as in L-plates for learner drivers).
'e'+'motion'+'a'+'l'='EMOTIONAL'
(Other definitions for emotional that I've seen before include "Showing feelings like love or fear" , "Heart-warming" , "Poignant" , "Deeply feeling" , "Touching" .)