one_and_only
1. [ adjective ] eminent beyond or above comparison
Synonyms: nonpareil one peerless unmatched unmatchable unrivaled unrivalled matchless
Examples:

"matchless beauty" "the team's nonpareil center fielder" "she's one girl in a million" "the one and only Muhammad Ali" "a peerless scholar" "infamy unmatched in the Western world" "unrivaled mastery of her art"

Related terms: incomparable
Similar spelling:   on_and_off
  one_hundred_one
  one-and-one