Here are examples of the word/phrase "uncommon" used in a sentence and paraphrased in a sentence...
A rookie achieving a score that high is extremely uncommon.
A beginner achieving a score that high is profoundly unconventional.
Unicorns are very uncommon around these parts.
Unicorns are very unwonted around these parts.
While brobdingnagian and gigantic mean the same thing, brobdingnagian is more uncommon.
While brobdingnagian and gigantic mean the same thing, brobdingnagian is more unconventional.
Other Examples...