Undecided rhymes with:
decided, decided, decided, lopsided, subsided, abided, chided, collided, decided, derided, glided, lopsided, misguided, presided, prided, resided, subdivided, subsided, undivided
Undecided sounds like:
unadjust, unadjusted, unattached, undetected, undisguised, uneducated, unhedged, unindicted, unmatched, unmitigated, unnoticed, untaxed, untested, untouched