Incertain \In*cer"tain\, n. [Pref. in- not + certain: cf. F. incertain, L. incertus. See {Certain}.] Uncertain; doubtful; unsteady. -- {In*cer"tain*ly}, adv. [1913 Webster] Very questionable and of uncertain truth. --Sir T. Browne. [1913 Webster]