Ultra

A prefix, the same as the Latin ultra, beyond, having in composition the signification beyond, on the other side, chiefly when joined with words expressing relations of place; as, ultra-marine, ultra-montane, ultra-mundane, ultra-tropical, and the like. In other relations it has the sense of excessively, exceedingly, beyond what is common, natural, right, or proper; as, ultra-Catholic, ultra-conservative, ultra-democratic, ultra-democracy, ultra-despotic, ultra-liberal, ultra-radical, ultra-republican, and the like.

a. [Lat., from ulter, that is beyond or on the other side, from uls, beyond, from the pronominal root il, whence ille, that.] Disposed to go beyond others, or beyond due limit; radical; extreme; as, ultra measures.