Here are examples of the word/phrase "purportless" used in a sentence and paraphrased in a sentence...
As a martial artist, trying to compete with Karate Kid is purportless unless you travel to the future.
As a martial artist, trying to compete with Karate Kid is pointless unless you travel to the future.
Acting without a strategy that is at least half decent would be purportless.
Acting without a strategy that is at least half decent would be futile.
Other Examples...