- ഉണ്ടു - yes, there is; from ഉള് + തു (our friend ആദേശസന്ധി) (This word also happens to be the past tense of ഉണ്ണുക - to have a meal.)
- ഉണ്ടാകുക - to come into existence, by extension
- ഉള്ള - having
- ഉള്ളത് - by extension, truth
- ഉണ്മ - verity, truth; from ഉള് + മ (ആദേശസന്ധി yet again)
- ഉള്ളം - mind, that which is "inside" a person
- ഉള്ളില് - inside; an interesting construction since it comes from ഉള് + ഇല്് , both noun and suffix meaning inside
- ഉള്ളി - onion! (I added it here because I think an onion is called ഉള്ളി because of the many "insides" that it has.)
What about non-existence?
ഇല്ല is the simplest word denoting non-existence. It can mean "no" or "not". As a suffix, ആ is also used to denote the negative. e.g. കുടാ - cannot join.