Even to a first-class student, it means 'trouble' (3)
I believe the answer is:
ail
'trouble' is the definition.
(synonyms)
'even to a first-class student' is the wordplay.
I cannot really understand how this works, but
'a' is found in the answer.
'first' could be 'i' (I in Roman numerals eg Elizabeth I) and 'i' is found in the answer.
'student' could be 'l' (as in L-plates for learner drivers) and 'l' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'it means' is the link.
Can you help me to learn more?
(Other definitions for ail that I've seen before include "Be unwell, suffer" , "Bother" , "pain" , "upset" , "Go sick" .)