DECREPITLY
Etymology
Adverb
decrepitly (comparative more decrepitly, superlative most decrepitly)
In a decrepit way.
Source: Wiktionary
DECREPIT
De*crep"it, a. Etym: [L. decrepitus, perhaps orig., noised out,
noiseless, applied to old people, who creep about quietly; de- +
crepare to make a noise, rattle: cf. F. décrépit. See Crepitate.]
Definition: Broken down with age; wasted and enfeebled by the infirmities
of old age; feeble; worn out. "Beggary or decrepit age." Milton.
Already decrepit with premature old age. Motley.
Note: Sometimes incorrectly written decrepid.
Source: Webster’s Unabridged Dictionary 1913 Edition