to watch, look at, check out, to subdue, bring under control
Je veux juste descendre du train, aller mater un jardin zen, genre.
I just want to get off the train and go check out a Zen garden, like.
— Bullet Train (2022)
Arrête de mater des films de cul et va travailler !
Stop watching porn and go to work!
— Juno (2007)
He needs to be subdued, that's all.
— Harry Potter et l'Ordre du Phénix (2007)
Tu vas le mater tout l'après-midi ?
Are you going to watch him all afternoon?
— Demain tout commence (2016)