Severely means to a very serious degree, or harshly. Severely injured, severely limited, punished severely.
It is the word medicine and news reporting use for the worst end of a scale: severely injured is a defined category rather than a description. The second sense is about manner, and speaking severely means with cold disapproval.
1adverbseverelyTo a very serious degree, or harshly.
“The town was severely damaged by the earthquake.”
severely is a degree.
Proto-Indo-European
*seǵʰ-
Latin
severus — severe, serious, grave in demeanor
English
severe
English, today
severely
From severe + -ly. severe comes from Middle French -, from Latin severus (“severe, serious, grave in demeanor”).
Etymology from Wiktionary, CC BY-SA