1: A beautiful girl at the beach that makes a hot pink bikini look good. Usually includes the suffix, "girl, chick, babe, etc" in order to not be confused with the second definition.
2: An Obese african american wearing a tiny pink jacket. This definiton is used very rarely, in fact, it's creation was meant to throw off users of the word. But hey, if you see this in real life, that's great!
1: "Dude look at that pinkini girl over there, long tan legs, firm ass, perfect set of breasts and a pair of sensual lips... and a pink bikini!"
"That's my sister."
2: "Oh look over there Marion, it's a fat black man wearing a tiny pink jacket, isn't there a word for that?"
"Yes dear, i believe it's, "a Pinkini"
"Huh, you don't see that every day."