资料来源 : pyDict

无疑,必定

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Undoubted \Un*doubt"ed\, a.
   Not doubted; not called in question; indubitable;
   indisputable; as, undoubted proof; undoubted hero. --
   {Un*doubt"ed*ly}, adv.

资料来源 : WordNet®

undoubtedly
     adv : with certainty; "it's undoubtedly very beautiful" [syn: {doubtless},
            {beyond question}, {without doubt}, {beyond any doubt}]