partner

Noun

• a person who is a member of a partnership

• an associate in an activity or endeavor or sphere of common interest
  • the musician and the librettist were collaborators
    
  • sexual partners
    

• a person's partner in marriage

Verb

• act as a partner
  • Astaire partnered Rogers
    

• provide with a partner

Related words

• Synonyms: 
  collaborator , cooperator , pardner , spouse , married person , mate , better half