Something or someone that is so cool the meaning is useless when applied to said person/thing. In times like these, one must use the correct Really Cool to verbalize the utter coolness of said holy object...person/thing.
Beatrice: Man, that Johnny sure is a jive cat.
Harriet: One might say he is... REALLY COOL.
Beatrice: No. BLASPHEMER! ROT IN HELL!!
By Milka
Really Cool
Something you call someone when you really like them and have a hugecrush on them but don’t want to say it
Wow that was really cool. Wow that was really cool. Wow that was really cool. Wow that was really cool.... The endless loop made by Dani... Remember to Drink Milk
Wow that was really cool. Wow that was really cool. Wow that was really cool. Wow that was really cool...
He's described as a "Really Cool Guy" at the party but beyond the fact that he carries cocaine around just to get attention he is really not very interesting at all.