The following "definition" comes from urbandictionary.com:
Similar to metrosexual but one who lives in the mountains or otherwise pursues the outdoors adventure lifestyle. Kind of a cleaned-up granola, a Woodsy GQ kinda guy with a splash of bohemian. Knows that he doesn't have to look or smell like a dirtbag to enjoy climbing, hiking, cycling, skiing (all forms), snowshoeing, etc. Probably reads Men's Journal, Outside, Outside's Go, National Geographic Adventure, even Wallpaper and Dwell. Brands: Patagonia, Keen, Kuhl, The North Face, Mountain Hardwear, Marmot, Mountain Khakis. Strong environmental ethic. Drives a well-maintained truck, performance SUV, or cross-over when absolutely necessary but walks or rides a bicycle whenever possible. Works out gym but primarily to be in shape for outdoor pursuits. Shuns chain stores and shops in outdoor specialty stores such as The Trailhead in Buena Vista, Colorado.
"For such an outdoorsy guy, that dude sure has great style."
"Yeah, he's a veritable MountainSexual!"
You can buy a beer stein, mug, T-shirt and other items with the definition for the MountainSexual in your life at urbandictionary.com.
via Mountain Khakis on twitter