Kourtney Kardashian -- MILF On the Prowl After Disick Break-Up (PHOTO)

Kourtney Kardashian's wasting no time getting her single chick swagger on -- she got all done up for a night out with her sisters ... the day after cutting Scott Disick loose.

Kourtney was with Khloe and Kim Tuesday evening for a girls night meal at Casa Escobar in Thousand Oaks -- and you KNOW that fishnet dress and midriff-baring top were no coincidence.

Pay attention, Scott -- nothing says, "y'know you done messed up” ... like your ex hitting the town with her hot sisters in a man magnet outfit ... fresh off a body-tightening workout, no less.

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