Not likely to be true or to occur or to have occurred:
— Legislation on the question is highly unlikely.

synonym: improbable.

Roget 471: impossible; not possible etc. 470; absurd, contrary to reason; unlikely; unreasonable etc. 477; incredible etc. 485; beyond the bounds of reason, beyond the bounds of possibility, beyond the realm of possibility; from which reason recoils; visionary; inconceivable etc. (improbable) 473; prodigious etc. (wonderful) 870; unimaginable, inimaginable^†; unthinkable.    impracticable unachievable; unfeasible, infeasible; insuperable; unsurmountable^†, insurmountable; unattainable, unobtainable; out of reach, out of the question; not to be had, not to be thought of; beyond control; desperate etc. (hopeless) 859; incompatible etc. 24; inaccessible, uncomeatable^†, impassable, impervious, innavigable^†, inextricable; self-contradictory.    out of one's power, beyond one's power, beyond one's depth, beyond one's reach, beyond one's grasp; too much for; ultra crepidam [Lat.].    ... show more

Roget 473: improbable, unlikely, contrary to all reasonable expectation; wild [Coll.], far out [Coll.], out of sight [Coll.], outtasight [Coll.], heavy [Coll.].    rare etc. (infrequent) 137; unheard of, inconceivable; unimaginable, inimaginable^†; incredible etc. 485; more than doubtful; strange, bizarre (uncomformable) 83.    ... show more

Polish: nieprawdopodobny

Has little chance of being the case or coming about.

Having a probability too low to inspire belief.

synonyms: improbable, unbelievable, unconvincing.