coming at a subsequent time or stage; "the future president entered college at the age of 16"; "awaiting future actions on the bill"; "later developments"; "without ulterior argument"
lying beyond what is openly revealed or avowed (especially being kept in the background or deliberately concealed); "subterranean motives for murder"; "looked too closely for an ulterior purpose in all knowledge"- Bertrand Russell
If you say that someone has an ulterior motive for doing something, you believe that they have a hidden reason for doing it. Sheila had an ulterior motive for trying to help Stan. ulterior motive/purpose etc a reason for doing something that you deliberately hide in order to get an advantage for yourself (from ulter , from uls )
beyond or outside an area of immediate interest; remote; "a suggestion ulterior to the present discussion"; "without any purpose, immediate or ulterior"- G B Shaw