A Terp hound is a stoner that loves terps. These are the compounds that give different strains of marijuana their unique smell and taste. A terp hound prefers to smoke tasty, stinky weed.
They may focus on the smell and taste of the bud rather than the THC %.
"Whoa dude that weed is dank"
"Yeah brah, I'm a terp hound, I love that shit"