Definify.com
Webster 1913 Edition
Flatly
Flat′ly
,adv.
 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.
 Webster 1828 Edition
Flatly
FLAT'LY
, adv.1.
  Horizontally; without inclination.2.
  Evenly; without elevations and depressions.3.
  Without spirit; dully; frigidly.4.
  Peremptorily; positively; downright.He flatly refused his aid.
Definition 2025
flatly
flatly
English
Adverb
flatly (comparative more flatly, superlative most flatly)
-  In a definite manner; in a manner showing complete certainty.
- It was an accusation that he flatly denied.
 
 -  In a manner that shows no emotion.
- He replied flatly to the policeman's questions.
 
 
Usage notes
- In sense 1. the collocation is nearly always with a negative idea. To flatly deny. To flatly refuse. To flatly contradict. And so on, similarly.
 
Translations
in a manner showing complete certainty
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in a manner that shows no emotions
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