Noah Webster
Liable
LI'ABLE, adjective [Latin ligo. See Liege.]
1. Bound; obliged in law or equity; responsible; answerable. The surety is liable for the debt of his principal. The parent is not liable for debts contracted by a son who is a minor, except for necessaries.
This use of liable is now common among lawyers. The phrase is abridged. The surety is liable that is, bound to pay the debt of his principal.
2. Subject; obnoxious; exposed.
Proudly secure, yet liable to fall.
Liable, in this sense, is always applied to evils. We never say, a man is liable to happiness or prosperity, but he is liable to disease, calamities, censure; he is liable to err, to sin, to fall.