adv. 1. In a flat manner; evenly; horizontally; without spirit; dully; frigidly. [ 1913 Webster ]
He that does the works of religion slowly, flatly, and without appetite. Jer. Taylor. [ 1913 Webster ]
2. peremptorily; positively; plainly; forthrightly. “He flatly refused his aid.” Sir P. Sidney. [ 1913 Webster ]