Meaning

adjective lying beyond what is openly revealed or avowed (especially being kept in the background or deliberately concealed); ; - Bertrand Russell

adjective beyond or outside an area of immediate interest; remote; ; - G.B.Shaw

adjective coming at a subsequent time or stage

originFrom Latin ulterior (“further, more distant”), from ulter (“that is beyond”) + -ior (“more”).

Etymology from Wiktionary, CC BY-SA 3.0