Maksim didn’t pull any punches on "The TMZ Podcast" ... telling us he thought Anna was a "s****y dancer" and adding her standoffish vibe definitely won't win her any fans in the competition.

Maksim also dismissed the excuse that Anna’s shaky Cha Cha was just nerves ... saying he didn’t buy it for a second 'cause conning people takes guts and self-control -- something he said she has bundles off.

But, Maksim didn’t stop there -- he slammed the idea of letting a "professional liar" compete while countless dedicated dancers who’ve put in the work get overlooked. You’ll want to check out the full clip to catch all his fiery takes!

Of course, Maksim ain't flying solo in his discontent -- Anna’s been fending off a wave of critics ever since her casting news broke, proving she’s got a lot more than just dance moves to handle!

Judge Carrie Ann Inaba dove right into the drama on the season premiere, urging critics to cut Delvey some slack despite her shady history.