The ex-talk show host didn't have very nice things to say about J Lo on her most recent podcast episode -- recounting a time when Jen was on "The View," and claiming she was "deeply unpleasant" ... and, allegedly, not a very nice person -- at least according to MMC.

Take a listen ... Meg doesn't specify what year this all happened, but says that during a time when Jen was a guest on the show, she just wasn't all that sweet -- and didn't fake it either.

It's a tough review from Meghan here ... she goes on to describe J Lo's entourage as massive -- bigger than Kim Kardashian and Joe Biden's even -- and while she holds back some of the alleged dirty deets ... she makes it clear, her experience with her wasn't great.

Meghan even compares Jen and Kim specifically -- saying KK was a sweetheart on and off camera ... whereas she alleges J Lo simply wasn't ... and she's still bitter about it now.

The irony of all this mudslinging in Jen's direction is that Meghan starts her remarks by saying she doesn't wanna tack on extra bullying she feels J Lo is experiencing at the moment ... yet, she does exactly that with her unfiltered story. Both sides of the mouth.

It's just the latest bad headline for Jen -- this as she experiences personal and professional hardships.

We broke the story ... Jen and Ben are quietly trying to sell their $60 million Bev Hills mansion -- which signals they're heading for divorce. J Lo also just nixed her entire tour before it even got off the ground.