Kourtney Kardashian -- Bares Bangin' St. Barts Bikini Bod (PHOTO)

Kourtney Kardashian's Instagram bikini body is like a Drake diss song ... at this point, she's just kicking a man while he's down.

This latest one was snapped while on vacation in St. Barts, with Kourt wearing a swimsuit that seemed to perfectly match her backdrop.

She should have captioned this pic "Back to Back."