As a noun egomaniac
is a person obsessed with their own (supposed) importance.
As an adjective undefined is
lacking a definition or value.
Other Comparisons: What's the difference?
A person obsessed with their own (supposed) importance.
- He's a raving egomaniac , all he ever talks about is himself and how important he is.
Lacking a definition or value.
(mathematics, computing) That does not have a meaning and is thus not assigned an interpretation.
- The result of division by zero is undefined .