Rum drunk by a student, painting (5)
I believe the answer is:
mural
'painting' is the definition.
(I know that mural is a type of painting)
'rum drunk by a student' is the wordplay.
'drunk' is an anagram indicator.
'by' means one lot of letters go next to another.
'student' becomes 'L' (as in L-plates for learner drivers).
'rum' anagrammed gives 'mur'.
'mur'+'a'+'l'='MURAL'
(Other definitions for mural that I've seen before include "Wall design" , "Painting on a wall, fresco" , "Wall art" , "Wall-painting" , "Wall decoration" .)