Pelirojo is another term for marijuana, and it originated in the Bay Area by a group of teenage girls. It came to be known as pelirojo because pelirojo means red hair in spanish, but it has the word ojo in it which means eye, which then just became pelirojo in code, so nobody who knows english or spanish can know what the user is talking about. It can be a noun, adjective, verb, anything you want.
Has multiple meanings. Mainly used as an adjective which meanings depend on the tone. In a disgusted tone peligroso describes something gross or not likeable. In a positive tone it can mean something that is very cool or Ludacris. You can also use it to mean dangerous which is its spanish translation.
"Hey Carmen your outfit is looking pretty peligroso!"
"Yo Coco that shit is peligroso!
"Ew! Bitch get that peligroso shit out of my house!"
"Suki your cookies are peligroso!"