Synonyms for Undecided:

adj.

all (adjective)
unresolved, undetermined, open.
changing (adjective)
vacillating.
conflicting (adjective)
ambivalent.
irresolute (adjective)
fickle, fly-by-night, ambivalent, hesitant, undependable, capricious, inconsistent, volatile, halfhearted, erratic, unsure, unresolved, tentative, shrinking, impulsive, dillydallying, uncertain, irresolute, unwilling, irresponsible, weak, shifty, indecisive, changeable, double-minded, Shilly-shally, vacillating, infirm, yellow, Flitting, watery, insipid, shy, spineless.
not sure, not definite (adjective)
dubious, debatable, unsettled, undetermined, uncommitted, tentative, indefinite, torn, moot, indecisive, doubtful, ambivalent, unsure, unfinished, vague, of two minds, on the fence, hesitant, irresolute, uncertain, up in the air, open, in the middle.
pending (adjective)
in the balance.
uncertain (adjective)
arguable, moot, changeable, mysterious, disputable, confused, tentative, deniable, controversial, unsure, questionable, uncertain, debatable, precarious, insecure, contestable, ambivalent, vague, unconvinced.

n.

cushion, aggregate, bury, assist, concede, chalk something up, attack, deadlock, all. circumstantial, effectively, dubious, fateful, unique, skeptical, paradise, effective, face to face, doubtful, situated, be better/worse off. undecided (noun)
on the fence, unresolved, indecisive, unsettled, open, uncommitted, undetermined.
undetermined (noun)
unconcluded, at a loss, unfinished, dubious, up in the air, in the balance, in the middle, of two minds, doubtful.

Other synonyms:

fateful, effectively, torn, indecision. circumstantial, doubtful, unique, situated, agonized, skeptical. agonizing, effective, dubious, face to face, paradise. reserve, indefinite. uncommitted
uncommitted.
undetermined
undetermined.

Usage examples for undecided

  1. My fate their captain still left undecided – Wilson's Tales of the Borders and of Scotland, Vol. XX by Alexander Leighton
  2. The young girl made a courtesy and stood undecided – A Little Girl in Old Philadelphia by Amanda Minnie Douglas
  3. For once he was undecided – Five Little Starrs in the Canadian Forest by Lillian Elizabeth Roy Elizabeth Colborne