English
infirmly
From infirm + -ly.
A compound of infirm + -ly
Proto-Italic *en- ‘in, into, in-’
Latin firmus ‘strong, firm’
Latin infirmus ‘weak, feeble’
Middle English infirme
English infirm
Today it means
adv In an infirm manner; feebly.
Language periods are conventional ranges, not dates for this word.
Etymograph / infirmly