Scowl at spilt lager (5)
I believe the answer is:
glare
'scowl' is the definition.
(thesaurus)
'spilt lager' is the wordplay.
'spilt' indicates an anagram.
'lager' with letters rearranged gives 'GLARE'.
'at' acts as a link.
(Other definitions for glare that I've seen before include "Too-bright light" , "Shine intensely" , "Large (anag.)" , "Stare fiercely - 5 down (anag)" , "Dazzling light (of publicity?)" .)