adulterous partner (in a relationship); adulterous lover
opponent; adversary; the competition; the other side; one's enemy
person with whom to speak; someone to talk to; companion; advisor; adviser
marriage partner; spouse; wife-to-be; husband-to-be; future spouse
other party; opposite party; opposing team; one's opponent; one's adversary
other party; opposite party; opposing team; one's opponent; one's adversary
other side; other party; other end (e.g. of phone connection); opposition
adviser; someone to consult with; someone to turn to about one's concerns; confidant
out of one's league; facing a too tough opponent; outclassed
person one is dating; significant other; partner; boyfriend; girlfriend
person with whom one is having an illicit love affair; mistress; lover
changing one's attitude or response according to who one is talking to or dealing with
worthy opponent; good match for someone; well-matched adversary
communications partner; entity at the end of a communication
the other party (usu. in business); person or party with whom you are dealing (on the other end)
opponent's side of court (in tennis, etc.)
interviewee; subject of an interview
opponent's territory (comp. karuta); the section of the playing field where one's opponent places their cards
recipient (of email, e.g.)
permanent virtual connection; PVC
switched virtual connection; SVC
opponent team; opposing team
competitor; rival; competition