low ‧ er 3 BrE AmE ( also lour British English ) /ˈlaʊə $ -ər/ verb [intransitive] literary
1 . when the sky or the weather lowers, it becomes dark because there is going to be a storm SYN darken :
lowering clouds
2 . to look threatening or annoyed SYN frown :
The other driver lowered at us as we passed him.