one - noun

the smallest whole number or a numeral representing this number

a single person or thing

one - adjective

• used of a single unit or thing; not two or more
• having the indivisible character of a unit
• of the same kind or quality
• used informally as an intensifier
• indefinite in time or position
• being a single entity made by combining separate components
• eminent beyond or above comparison

one - thesaurus

ace   ane   matchless   nonpareil   peerless   single   unitary   unity   unmatchable   unmatched   unrivaled   unrivalled