What does "Nolite te bastardes carborundorum" mean in Latin?

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Why: It is carved in the wall of Offred's bedroom in The Handmaid's Tale. I'm pretty sure the Latin name for sapphire / ruby is similar to carborundorum.

Answer: It's fake Latin for "Don't let the bastards grind you down." Other variations (none of them correct) include:

• Illegitimi non carborundum
• Nil illegitimi carborundum.
• Non illegitimis carborundum.
• Illegitimi nil carborundum.
• Non illegitimi carborundum.
• Nil bastardo carborundum.
• Nolite te bastardes carborundorum.
• Illegitimis non carborundum.
• Illegitimus non carborundum est.
• Nil illegitimo in desperandum carborundum
• Nil carborundum illegitamae

Source: Word Reference Forum / Wikipedia

The More You Know: The Latin name for sapphire / ruby is corundum - though carborundum is a hard mineral used for grinding. The fake word word carborundorum is probably a portmanteau of "carbon" and "corundum." So I was kind of right. Again.