From BiblePortal Wikipedia

King James Dictionary [1]

Parta'Ker, n. One who has or takes a part, share or portion in common with others a sharer a participator usually followed by of.

If the Gentiles have been made partakers of their spiritual things--  Romans 15

Sometimes followed by in.

Wish me partaker in thy happiness--

If we had been in the days of our fathers, we would not have been partakers with them in the blood of the prophets.  Matthew 23

1. An accomplice an associate.

When thou sawest a thief,thou consentedst with him, and hast been partaker with adulterers.  Psalms 1

Webster's Dictionary [2]

(1): ( n.) One who partakes; a sharer; a participator.

(2): ( n.) An accomplice; an associate; a partner.