1660s, from un- (1) "not" + decisive. The usual word is indecisive.

Online Etymology Dictionary, © 2010 Douglas Harper

Examples from the Web for undecisive

Historical Examples of undecisive

  • The proceedings being merely a prelude to a higher court, the jurors rendered an undecisive verdict.

    In Friendship's Guise

    Wm. Murray Graydon

  • The summer passed away with many but undecisive battles, until the storms of the long northern winter separated the combatants.

    The Empire of Russia

    John S. C. Abbott

  • A number of sieges and undecisive skirmishes now followed, which brought upon the Christians the jeers and scoffs of the Turks.

  • No sooner had he gotten over, however, than he was attacked by the Confederates and a severe but undecisive engagement followed.

    The Civil War Through the Camera

    Henry W. (Henry William) Elson

  • The slaughter continued until late in the night and was undecisive.

    Battles of the Civil War

    Thomas Elbert Vineyard