Source : Webster's Revised Unabridged Dictionary (1913)

Effusive \Ef*fu"sive\, a.
   Pouring out; pouring forth freely. ``Washed with the effusive
   wave.'' --Pope.

   {Effusive rocks} (Geol.), volcanic rocks, in distinction from
      so-called intrusive, or plutonic, rocks. --
      {Ef*fu"sive*ly}, adv. -- {Ef*fu"sive*ness}, n.

Source : WordNet®

effusively
     adv : in an effusive manner; "the critics praised her effusively"