When he was still a normal street Meowth, the future Meowth of Team Rocket fell in love with Meowzie. However, she rejected him as her owner could buy her anything she wanted and Meowth, conversely, had nothing to offer. To try to win her love, Meowth tried to make himself more human by walking on two legs and learning how to talk in the human language, but she still rejected him on the grounds that he was now a freak Meowth.
Years later, after returning to Hollywood in Go West Young Meowth, Meowth met Meowzie again, now a member of his old Meowth street gang after she'd been abandoned by her Trainer. When the gang tried to force Meowth to rejoin them, Jessie and James drove them off with James's Weezing's Smog, and Meowth subsequently defeated the gang's Persian leader in battle. However, although Meowzie didn't want to join the gang, she told Meowth that she wouldn't feel right abandoning the Persian after he took her in, and admitted that she still didn't want to be with a freak Meowth despite all that he had done for her.
In A Hole Lotta Trouble, Max asked Meowth how it was possible that he could talk since he is a Pokémon. When Meowth started to tell his history to Max, a flashback of him with Meowzie in the windows appeared.
In accordance to her wealthy upbringing, Meowzie has always been a vain and spoiled Pokémon who tends to look down on those who are financially beneath her, deeming Meowth as a lowly street urchin and refused his advances based solely on the fact her Trainer could afford anything she wanted. Years later after being abandoned by her Trainer and becoming a street urchin herself, Meowzie still showed great apathy and ungratefulness towards Meowth, as despite him having done much for her after their reunion, she still considered him a freak for being able to talk human language and showed zero appreciation for his efforts in trying to make her happy, and to keep her safe.
Her lack of gratitude and general display of disdain seems to focused exclusively on Meowth, however, as after she was taken in by his former Meowth gang, led by a Persian, Meowzie showed great loyalty and affection for them, despite their aggressive attempts to recruit her, and claimed she couldn't abandon them after everything they've done for her, an exact contrast of her attitude towards Meowth, who himself had gone above and beyond for her sake.
In the manga
Meowzie and her kitten in Pokémon: The Electric Tale of Pikachu
The Electric Tale of Pikachu
In Days of Gloom and Glory, Meowth reminisces about a "pretty li'l Meowth" that he knew when he used to live in the back alleys of a big city. Though she is not mentioned by name in the manga, the circumstances surrounding her and her relationship with Meowth are very similar to Meowzie's. In the manga, Meowzie finds Meowth's ability to speak human language "creepy" and she has had at least one kitten, a small, tough Meowth that was recovered from a Poké Ball found in a flood.
