A performance you might describe as "mesmerizing"?

Mia Kirshner in The Black Dahlia. She is so haunting that she transfixes me whenever she's on the screen. It really is like looking at a ghost.

A recent favorite of mine is Robert Carlyle in Ravenous.
It's technically three performances in one: him making us pity him / him in a uniform and "winning" mode / him on an unfiltered monster mode... and he goes between them so seamlessly (without incredibly obvious facial expressions like a Jack Nicholson or Nicolas Cage would do).
The scene that wowed me the most was where he's holding up his bleeding hand in front of Pearce and asking if he misses the taste of it... It actually comes off as seductive.
He owns the role and the film (which is bonkers) so hard and makes it look so easy.

Salma Hayek in From Dusk Till Dawn.

Well see here is where Kathryn Hunter belongs - not in "the best performance of 2021" - for what a 2-3 scene conceptual stunt?..........come on MAR - get your heads in the game ffs

Also.......those performances like Maria Falconetti in The Passion of Joan of Arc or Anna Karina in Vivre Sa Vie....where you're not sure how the performance is registering so much and that it then feels "like a kind of magic trick".........usually this word - to me - pertains more to the role or it's "better" suited to use in conjunction to the role ......but I'm sure I've used it synonymously /shorthand with "great" also.....for men: Bardem in Biutiful is one.....

Sandrine Bonnaire in To Our Loves immediately came to mind

Anne-Louise Lambert in Picnic at Hanging Rock is a mesmerizing performance because to be mesmerizing is practically all she's required to do. Lambert is coolly aloof with a knowing smile in all her scenes which hints at a higher level of consciousness and awareness that separates her from the rest of her peers and makes her such a source of obsession for the Dominic Guard character (the audience surrogate) who is literally mesmerized by her. With him, we follow her down the rabbit hole.

Ernest Borgnine rightly gets lauded for his Oscar-winning performance in Marty (one of the best Oscar wins, both in terms of performance and picture), but that movie doesn't work as well as it does without the marvelously enchanting Betsy Blair as Clara. Such a poignant portrayal of shyness and vulnerability -- something about it feels painfully raw, like an exposed nerve. I think Betsy Blair could've enjoyed a career like Mary Steenburgen if she had been born a couple of decades later.

I definitely want to make room for these delicious, movie-stealing villain performances: Javier Bardem in No Country for Old Men, Heath Ledger in The Dark Knight, and Christoph Waltz in Inglourious Basterds. Actors in complete control of their craft, owning every scene they're in - as an audience, we're totally taken away by it. 

LOL, that was majestic, I actually want to see it now. Laughed so hard when he said "family".