What is a synonym for ultimate?

Here are some synonyms for "ultimate", depending on the context:

General:

* Supreme

* Highest

* Final

* Last

* Absolute

* Perfect

* Ideal

* Greatest

* Chief

* Principal

* Topmost

Specific:

* Fundamental (when referring to a basic principle)

* Definitive (when referring to something definitive)

* Unmatched (when referring to something unbeatable)

* Undisputed (when referring to something not questioned)

Informal:

* Best

* Top

* Number one

The best synonym will depend on the specific meaning and context of the word "ultimate" in your sentence.