Derek Hough -- I'm Not Saying I'm NOT Dating Kate Hudson

Derek Hough isn't ready to admit he's banging Kate Hudson -- but he's definitely not denying it either.

The "Dancing with The Stars" pro was in Boca Raton Thursday -- at a Tony Robbins seminar of all things -- when a photog popped the question about rumors he and newly single Kate are hooking up ... and his response is a little weird.

Hough and Huds were reportedly making out at an L.A. hot spot last Friday night -- he left out the front door, and she was spotted sneaking out the back -- sans engagement ring.

So, Derek ... if you're NOT with her ... why not just say so? Just sayin'.