Synonyms for Showed once for all:

• v.

  •prove (verb)
  • certify,
  • convince,
  • trial,
  • find,
  • bear out,
  • test,
  • manifest,
  • experiment,
  • demonstrate,
  • make evident,
  • validate,
  • confirm,
  • justify,
  • show clearly,
  • warrant,
  • evince,
  • affirm,
  • determine,
  • fix,
  • ascertain,
  • declare,
  • examine,
  • analyze,
  • have a case,
  • result,
  • try,
  • show,
  • verify,
  • back,
  • attest,
  • witness,
  • settle,
  • end up,
  • substantiate,
  • check,
  • show once and for all,
  • sustain,
  • evidence,
  • explain,
  • document,
  • pan out,
  • turn out,
  • authenticate,
  • corroborate,
  • add up,
  • uphold,
  • testify,
  • assay.

Antonyms for Showed once for all:

• v.

  • prove
    disprove, discredit, hypothesize, theorize.