Leaving your facebook account up, allowing any intruder to access your profile. This status usually includes some falsely incriminating statement about the victim.
Why does my status say '@Greg has a small penis?!'"-- "Ooooh.. sorry. Looks like you left your profile up. Rookie mistake.
Falling in love with a girl prematurely.
"Man! Look at that idiot! He fell for that slut after one night! She totally blew him off!"
"What a fool. It must be his first time with a girl."
"True man. We've all made those rookie mistakes."
An egregious error (or altogether unwitting, on the other end of the spectrum of awareness) resulting in a response ranging from a harmless prank to serious vandalism (Localized to York, PA)
It was a major rookie mistake for him to leave his car door open!
The act when someone makes a mistake that is so stupid, he is considered a rookie at it. The person must be called a rookie until the event is forgotten about, which in most cases takes a long time. Sucks for the rookie.
Person 1: Whats a rookie mistake?
Person 2: Thats a rookie mistake for not knowing what a rookie mistake was!
Person 1: Ahh man!