noun: derisive term for a recruit, trainee, or new member to an organization who is untrained and not yet educated/adjusted to the organizations working practices or culture, one who continually embarrasses him/herself and others with ignorant and inappropriate behavior. Term is military in origin, short for "slick-sleeves" referring to an E-1 or lowest rank in the military (Airman Basic in USAF, Private in Army or Marine Corps), as these individuals have no stripes on their uniforms, hence "slick sleeves". Term is liberally used in basic training during the first week when a D.I. (drill instructor) has yet to learn the name of all recruits in his platoon/squadron.
(Drill Instructor): "Forward, March!"
(Drill Instructor): "NO, Slick, start on your OTHER left foot!"