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.
Proto-Indo-European root meaning "to tie, bind."
It forms all or part of: alloy; ally; colligate; deligate; furl; league (n.1) "alliance;" legato; liable; liaison; lien; lictor; ligand; ligament; ligate; ligation; ligature; oblige; rally (v.1) "bring together;" religion; rely.
It is the hypothetical source of/evidence for its existence is provided by: Latin ligare "to bind;" Albanian lidh "I bind," and possibly Middle Low German lik "band," Middle High German geleich "joint, limb."
"liable to be doubted," 1620s, from French dubitable, from Latin dubitabilis "doubtful," from dubitare "hesitate, doubt" (see doubt (v.)). Related: Dubitably.
1510s, "liable to sin, morally weak;" c. 1600, "liable to break;" a back-formation from fragility, or else from French fragile (Old French fragele, 14c.), from Latin fragilis "easily broken," from root of frangere "to break" (from PIE root *bhreg- "to break"). Transferred sense of "of frail constitution" (of persons) is from 1858.