Source : Webster's Revised Unabridged Dictionary (1913)

Mulish \Mul"ish\ (m[=u]l"[i^]sh), a.
   Like a mule; sullen; stubborn. -- {Mul"ish*ly}, adv. --
   {Mul"ish*ness}, n.

Source : WordNet®

mulishly
     adv : in a stubborn unregenerate manner; "she remained stubbornly
           in the same position" [syn: {stubbornly}, {pig-headedly},
            {obdurately}, {obstinately}, {cussedly}]