1590s, "unable to pay one's debts," from in- (1) "not" + Latin solventem "paying" (see solvent). Originally of one who was not a trader; only traders could become bankrupt.
an insolvent estate
an insolvent person
insolent
insolubility
insoluble
insolvable
insolvency
insolvent
insomnia
insomniac
insomuch
insouciance
insouciant