Mighty is defined as possessing great and impressive power or strength, especially on account of size.

Epic, dope, cool, nitro, mega, awesome, sweet, boss, bank, sick, wicked, rad, gnarly, etc.

A word used to descibe the word "really". Used in literal tense and sarcastic tense. Literal would be, "Wow, he is mighty gay". Sarcastic would be "Wow, your mighty cool". This sentence would be used when someone did something they thought was cool, but it wasn't.