"undefined" in the adjective sense
1. undefined, vague
not precisely limited, determined, or distinguished
"an undefined term"
"undefined authority"
"some undefined sense of excitement"
"vague feelings of sadness"
"a vague uneasiness"
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License