A person that exhibits the qualities that pertain to being both a scrub and a rookie.
"Zach, did you just one-star the 23rd player in the clan war?"
"Yea..."
"You're literallythe biggest scrookie I know."
"Yea, I guess that was pretty scrookish of me."
Best friend, buddy, or roommate that you do shrooms with. You can use this term to call your friends even if you don't do shrooms, or do shrooms with them. In other words, you can just be good friends with them and not do shrooms, or just not do shrooms with them, or you can. It goes either way. Alternatively, "shroomie" can just mean good friend.