Meaning : Lying beyond what is openly revealed or avowed (especially being kept in the background or deliberately concealed).
Example :
Subterranean motives for murder.
Looked too closely for an ulterior purpose in all knowledge.
Synonyms : subterranean, subterraneous
Meaning : Beyond or outside an area of immediate interest. Remote.
Example :
A suggestion ulterior to the present discussion.
Without...any purpose, immediate or ulterior.