Aragorn: its mordor
Aragorn: its "mordor", with a "d"
Boromir: one does not simply walk into mordor...
Frodo: um... yes you do...
Boromir: shut up!,no you dont!
Frodo: yes you do, you tottally do
Boromir: nuh-uh!. you need like... an army.
with, like... ninjas... and... um... wizards!
Gandalf: i'm a wizard!
Boromir: yeah, but you're not a ninja
maybe some bears, too... bears that shoot laser beams out of their eyes. oh man, that would be so frickin' AWESOME!
2) a mysterious place of power, where the dark elite resides
3) a place that might or might not be real, depending on the definition
"One does not simply <activity> oneself into Mordor." discredits <activity> by stating that it does not live up to one's own impossibly inflated (and potentially misguided) standards.
<Alakala> One does not simply warez himself into Mordor.
<CHINA> One does not simply use an overused meme to answer me into mordor
Mordor was a relic of the devastating works of Morgoth, apparently formed by massive volcanic eruptions. It was given the name Mordor already before Sauron settled there, because of its volcano Orodruin and its eruptions.
Mordor actually has two meanings: "The Black Land" in Tolkien's contrived language Sindarin, and "The Land of Shadow" in Quenya. The root mor ("dark", "black") also appears in Moria. Dor ("land") also appears in Gondor ("stone-land") and Doriath ("fenced land"). The Quenya word for Shadow is "mordo".
A proposed etymology out of the context of Middle-earth is Old English morthor, which means "mortal sin" or "murder". (The latter are descended from the former.) It is not uncommon for names in Tolkien's fiction to have relevant meanings in several languages, both those invented by Tolkien, and "real" ones, but this of course happens with any two languages. Mordor is also a name cited in some Nordic mythologies referring to a land where its citizens practise evil without knowing it, imposed on themselves by the society long created for that purpose. This quite fits with Tolkien's Mordor.