Two or more things that can’t be compared with each other are uncomparable. Something that is so good that it is beyond comparison is incomparable. Some dictionaries don’t list uncomparable, and your spell-check may catch it, but it’s a perfectly good word. It fills a useful role not filled by incomparable.
The two words are usually pronounced similarly—in-COM-parable and un-COM-parable—though uncomparable is sometimes pronounced un-cum-PAIR-uhble.
Examples
Today it is cattle grazing on private ranches that preserves 20 million acres of incomparable landscape. [San Francisco Chronicle]
With some words the two languages seem to mirror each other; and sometimes the two lingos are uncomparable. [SemTribe]
Kobe Bryant remains incomparable, but Fisher, Brown, Blake and Artest suddenly appear weak, making the team vulnerable. [SportsFanLive]
… but the quantity of it is uncomparable to the number of those in the language of Shakespeare. [Spotted by Locals]
