Hug cold student having drunk gin (5)
I believe the answer is:
cling
'hug' is the definition.
(thesaurus)
'cold student having drunk gin' is the wordplay.
'cold' becomes 'c' (eg on taps).
'student' becomes 'l' (as in L-plates for learner drivers).
'having drunk' indicates anagramming the letters (I've seen 'have drunk' mean this (I've seen this in other clues)).
'gin' with letters rearranged gives 'ing'.
'c'+'l'+'ing'='CLING'
(Other definitions for cling that I've seen before include "Adhere to - ring" , "act like limpets" , "Clasp closely" , "Keep hold" , "Adhere, hold tight" .)