The Collaborative International Dictionary
Ultroneous
Ultroneous \Ul*tro"ne*ous\, a. [L. ultroneus, from ultro to the
further side, on his part, of one's own accord. See
Ultra-.]
Spontaneous; voluntary. [Obs.]
--Jer. Taylor. --
Ul*tro"ne*ous*ly, adv. [Obs.] -- Ul*tro"ne*ous*ness, n.
Wiktionary
ultroneous
a. (context archaic English) spontaneous; voluntary