Underdog. Underrated. Undercover. Slept-on. Whatever you want to call 'em, there's a certain set of rappers out there that haven't been given the critical plaudits and/or hit success commiserate to their level of talent. And every dog (or dogg, or underdogg) deserves their day.

But don't get it twisted: This isn't a ranking of rappers in regards to their skill or talent. While everyone on this list has demonstrated undoubtedly impressive artistic aptitude at one point or another, we're judging "Greatest" and "Slept-On" by how slept-on these artists are, relative to the greatness of their respective catalogs.

There are MCs at the lower end of the list, like Nipsey Hussle, who don't necessarily have vast, essential discographies, but are far better than their level of popularity would ever suggest. At the opposite end of the spectrum, there are certified legends. Take guys like Big Pun, for example, who—sure—get their fair share of props.

But if you ask us? Not enough. Especially considering the sheer technical prowess that are irrefutable facts of guys like Pun that put him on par with any other revered great.

There's a dual criteria for being slept-on, and both scenarios are legitimate examples. Rappers arrive at these dilemmas for a number of reasons: label drama, jail, being too left-field, getting stuck in a local scene, and being overshadowed by another member of a group, for starters.

And another thing: Claiming to be slept-on is as hip-hop as break beats. Every rapper has a lowercase-c complex about being "the best," and when they're not recognized as such, talk of under-appreciation inevitably follows.

But: Some rappers who won't stop ranting about their "haters" do, in fact, have a point. Hell, plenty of MCs who are generally liked and never complain about being overlooked still deserve more praise than they've ever been awarded. It's time for that to change.

Here at Complex, we've been thinking about those slept-on rappers. From the respected vets whose legacies have diminished at an astonishingly accelerated rate, to the amazing artists who are, unfortunately, only known to a select few.

These are The 50 Most Slept-On Rappers of All Time...