Solution

SINGULAR

3 clues

Exceptional

Word class: Common adjective
Nature of clue: Synonym
Difficulty: Easy
Sources: Boatload Puzzles

Other solutions to Exceptional

Not plural

Word class: Common adjective
Nature of clue: Description
Difficulty: Easy
Sources: Boatload Puzzles
Topics: Languages - Writing Systems

Unique

Word class: Common adjective
Nature of clue: Synonym
Difficulty: Very easy
Sources: Boatload Puzzles

Other solutions to Unique

Words are categorized by artificial intelligence: there can be mistakes.