confederate

/K AH0 N F EH1 D ER0 AH0 T/
noun
  1. 1

    A member of a confederacy.

  2. 2

    An accomplice in a plot.

  3. 3

    An actor who participates in a psychological experiment pretending to be a subject but in actuality working for the researcher (also known as a "stooge").

verb
  1. 1

    To combine in a confederacy.

adjective
  1. 1

    Of, relating to, or united in a confederacy

  2. 2

    Banded together; allied.

Source: https://en.wiktionary.org/wiki/confederate