Exceptional

1. Forming an exception; not ordinary; uncommon; rare.
2. Better than the average; superior due to exception or rarity.
3. (geometry) Corresponding to something of lower dimension under a birational correspondence.

Synonyms

• excellent
• egregious (most often used negatively, however)

Antonyms

• (forming an exception): ordinary, categorical, common, general, usual
• (superior due to exception or rarity): ordinary, mediocre, commonplace