mid-15c., "bound or obliged by law," probably from Anglo-French *liable, from Old French lier "to bind, tie up, fasten, tether; bind by obligation" (12c.), from Latin ligare "to bind, to tie" (from PIE root *leig- "to tie, bind"). With -able. Perhaps from an unattested word in Old French or Medieval Latin. General sense of "exposed to" (something undesirable) is from 1590s. Incorrect use for "likely" is attested by 1850.