acquaintance

Noun

• a person with whom you are acquainted
  • I have trouble remembering the names of all my acquaintances
    
  • we are friends of the family
    

• a relationship less intimate than friendship

• personal knowledge or information about someone or something

Related words

• Synonyms: 
  friend , acquaintanceship , familiarity , conversance , conversancy
• Antonyms: 
  stranger , alien , unknown