WordNet (r) 3.0 (2006):

do away with
    v 1: terminate, end, or take out; "Let's eliminate the course on
         Akkadian hieroglyphics"; "Socialism extinguished these
         archaic customs"; "eliminate my debts" [syn: extinguish,
         eliminate, get rid of, do away with]

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "do away with":
   abolish, abrogate, annihilate, annul, bereave of life, cancel,
   carry away, carry off, cast off, chloroform, countermand,
   counterorder, cut down, cut off, cut short, deprive of life,
   destroy, disannul, dispatch, dispel, dispose of, do for,
   do to death, eliminate, end, execute, exterminate, finish,
   finish off, fling off, get rid of, immolate, invalidate, kill,
   launch into eternity, liquidate, lynch, make away with, make void,
   martyr, martyrize, nip, nullify, override, overrule, poison, purge,
   put away, put down, put paid to, put to death, put to sleep,
   recall, recant, remove from life, renege, repeal, rescind, retract,
   reverse, revoke, sacrifice, set aside, shake off, shoo, slaughter,
   slay, starve, suspend, take life, take off, throw away, throw off,
   to, vacate, void, waive, withdraw, write off