Webster's Revised Unabridged Dictionary · 1913

Flatly

Flatly , adverb

1.
In a flat manner; evenly; horizontally; without spirit; dully; frigidly.
He that does the works of religion slowly, flatly, and without appetite. — Jer. Taylor
2.
peremptorily; positively; plainly; forthrightly.
He flatly refused his aid. — Sir P. Sidney