IPA: /ˈfraʊniər/
KK: /ˈfraʊniər/
Having a more displeased or unhappy expression than usual.
She looked frownier than ever when she heard the bad news.
Comparative: frownier
Superlative: frowniest
Frownier is formed from "frown" (from Old English "frynan", meaning to wrinkle or furrow the brow) and the suffix "-ier" (meaning more). The word "frownier" means more inclined to frown or having a more pronounced frown.
Think of someone who has a brow that is more wrinkled or furrowed — that's what frownier means, someone who frowns more.