I. adjective
also lour·ing ˈlau̇(ə)riŋ, -rēŋ esp in the South -au̇wər-
Etymology: Middle English louring, from present participle of louren to lower, frown — more at lower
: dark and threatening : gloomy , sullen , frowning
a lowering expression in her black eyes — Liam O'Flaherty
it was a lowering May day — Sylvia T. Warner
II. noun
( -s )
Etymology: from gerund of lower (IV)
: the act or an instance of making low or lower
a lowering of trade restrictions — Current Biography