The art of using social media to brag about outdoor adventures you never actually went on. A combination of "um" (hesitation) and "kayak" (because it sounds outdoorsy).
Can be used as a verb (to umiaq) or a noun (an umiaq post).
Sophie: "Check out my Insta! I'm totally crushing this mountain climb!"
Jake: "Dude, you're umiaqqing again. That's clearly the rock wall at Planet Fitness."