WordWeb Online

1. Lying beyond what is openly revealed or avowed (especially being kept in the background or deliberately concealed)
   "looked too closely for an ulterior purpose in all knowledge";
   - subterranean, subterraneous
    
2. Beyond or outside an area of immediate interest; remote
   "a suggestion ulterior to the present discussion"; "without...any purpose, immediate or ulterior"
    
3. Coming at a subsequent time or stage
   "without ulterior argument";
   - later, posterior

See also: covert, distant, remote, subsequent

Encyclopedia: Ulterior