Appears To Hurl Anti-Semitic Slur

Meyers Leonard is in some seriously hot water -- the Miami Heat center appeared to use an anti-Semitic slur during a recent video game stream this week ... and it was all captured on video.

The 29-year-old was playing "Call Of Duty: Warzone" on his Twitch channel -- which has nearly 70,000 followers -- when he seemingly says the following: "F***ing cowards, don't f***ing snipe me, you f***ing k*** bitch."

Yeah ... it's bad.

The comment was met with awkward laughter by other gamers on the stream ... but Leonard seemed to brush off the situation and kept playing.

Leonard has yet to address the incident -- he was actually still streaming on his channel early Tuesday afternoon -- but it's only a…