Uniform worn by crazy student, trendy and emotional (7)
I believe the answer is:
maudlin
'emotional' is the definition.
(similar in meaning)
'uniform worn by crazy student trendy' is the wordplay.
'uniform' becomes 'U' (phonetic alphabet: alpha, bravo, charlie etc.).
'worn by' is an insertion indicator (I've seen this in other clues).
'crazy' becomes 'mad' (synonyms).
'student' becomes 'l' (as in L-plates for learner drivers).
'trendy' becomes 'in' ('in' can mean fashionable).
'u' placed into 'mad' is 'maud'.
'maud'+'l'+'in'='MAUDLIN'
'and' is the link.
(Other definitions for maudlin that I've seen before include "Mushy and emotional" , "Foolishly tearful" , "Over-emotional" , "Weepy (and intoxicated?)" , "Effusively or insincerely emotional" .)