flunk

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To fail, especially in a course or an examination.
• intransitive verb To fail (an examination or course).
• intransitive verb To give a failing grade to (a student).
• intransitive verb To fail (a drug test, as for a performance enhancing substance).
• noun A failure.
• noun A failing grade.

from The Century Dictionary.

• To fail or give up; break down or back down, as from incompetence or fear: often with out: as, to flunk in a school recitation or examination; to flunk out from a contest.
• To cause to fail, as in a recitation or an examination.
• noun A failure or back-down; in colleges, a complete failure in a recitation or an examination.

from the GNU version of the Collaborative International Dictionary of English.

• noun College cant, U.S., College cant, U.S., U.S. A failure or backing out.
• transitive verb Colloq. U.S. To fail in; to fail to pass (a test, examination, or course of study).
• transitive verb To shirk, as a task or duty.
• intransitive verb To fail, as on a lesson; to back out, as from an undertaking, through fear.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb US, transitive, intransitive Of a student, to fail a class; to not pass.
• verb US, transitive Of a teacher, to deny a student a passing grade.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb fail to get a passing grade
• noun failure to reach a minimum required performance