The phrase "ultimate endeavor" is correct and usable in written English.
It can be used to describe a person's most significant or ambitious effort or goal.
Example: "Completing the marathon was my ultimate endeavor, a challenge I had been training for all year."
Alternatives: "greatest effort" or "final pursuit".
It is the ultimate communal endeavor.
That means the search for life is the ultimate 'win-win' endeavor.
When Chekhov completed "The Cherry Orchard" in 1904, he was dying, and the play, which he labeled a comedy, could be viewed as a final chortle of recognition at the vanity of human wishes and the ultimate absurdity of human endeavor in the shadow of mortality.
When asked what the ultimate utility of this endeavor was, Frank originally heard "futility" and when I corrected him told me that "What's the ultimate futility of this endeavor?" would have been a better question.
Finally, moral philosophy should say something about the ultimate end of human endeavor, the Highest Good, and its relationship to the moral life.
The ultimate aim of this endeavor was to give young female readers tips on how they could more effectively attract a foreign boyfriend.
Hence, the claim is based on the speaker's assessment of the ultimate capabilities of scientific endeavors, and such an assessment invokes philosophical speculations quite removed from statistical or practical research considerations.
Football is, as Ryan liked to say, "the ultimate team game," a group endeavor that calls for unified commitment.
It is often observed that while it is relatively easy to put forward a convincing theory in the outline, the ultimate test for any philosophical endeavor is whether the product will survive detailed specification (the devil is in the details, and so on).
Whatever the ultimate effect of her own creative endeavors, Young believes that art has steadfastly remained an effective tool for social change throughout the ages.
