Bella Hadid: TMZ Photog Offers Fashion Tips

Bella Hadid forgot to zip up her track suit ... or so our photog thought when he ran into her at LAX.

Bella was headed for parts unknown Thursday when he pointed out she was showing lots of skin. She was properly dismissive.

She also laughed off our question about intro'ing The Weeknd (aka Abel) to her fam.

Fun video.