"getting the basics wrong" ... especially when you should know the answer
Expecting to be able to buy tickets "on-the-door" when U2 are coming to play in the Village Hall that night... to discover that all 250 were sold out months ago...
Schoolboy Error: (n.), (der. old English), A mistake, often trivial, clumsy, dimwitted or easily avoided. Generally shameful in hindsight, but without cause for embarassment, owing more to circumstances or instantaneous bad luck, rather than serious incompetence of behalf of the maker. Derived from the "trial and error" psychology present in Victorian-era English public schools.
Upon dropping the soap in the Violent Offenders' Wing of Barwon Prison, Eric cursed his schoolboy error.
Dr. Feynmann lowered his glasses as the fruit of twenty minutes labour yielded an unwanted result: E = mc^2/0. "Well fuck me", he said, turning to the class. "I seem to have made a schoolboy error."
The most basic of errors. An error so simple, and avoidable, that anyone with an ounce of credibility or experience in that field should not be commiting it. A mistake that should only be made by school boys still in training for that particular task. Especially used when referring to playing games of pool in pubs, or occasionally during snooker. Schoolboy error can be heard ringing out by jeering onlookers if for instance a participant missed a sitter = he should have potted it as it as so simple, that thereforehe is reduced to the level of a lowly school boy playing his dad for the first time.
And here comes Keane for the winner....Oooooooh and he's missed, and left the black right over the pocket for Swann to tap in...
Schoolboy error!
another term for a station wagon, mini-van, or any other kind of vehicle that is targeted at the "family" demographic(also M.A.V.)
"Tactical advantages aside, the M.A.V. is top of the line for the holy warrior troop transport manufactured by the Church of Latter Day Saints Military Industrial Complex. Also great for family trips...to heathen lands."
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.