What is the meaning of the word "one-on-one"?

Definitions:

  1. (of two persons) in direct encounter copy to clipboard adverb
    • preferred to settle the matter oneonone copy to clipboard
  2. being a system of play in which an individual defensive player guards an individual offensive player copy to clipboard adjective
    • oneonone defense copy to clipboard
  3. directly between two individuals copy to clipboard adjective
    • oneonone instruction copy to clipboard

Synonyms: