fail

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

• intransitive verb To prove deficient or lacking; perform ineffectively or inadequately.
• intransitive verb To be unsuccessful.
• intransitive verb To be unsuccessful in being acted upon.
• intransitive verb To receive an academic grade below the acceptable minimum.
• intransitive verb To prove insufficient in quantity or duration; give out.
• intransitive verb To decline, as in strength or effectiveness.
• intransitive verb To cease functioning properly.
• intransitive verb To give way or be made otherwise useless as a result of excessive strain.
• intransitive verb To become bankrupt or insolvent.
• intransitive verb To disappoint or prove undependable to.
• intransitive verb To abandon; forsake.
• intransitive verb To omit to perform (an expected duty, for example).
• intransitive verb To leave undone; neglect.
• intransitive verb To receive an academic grade below the acceptable minimum in (a course, for example).
• intransitive verb To give such a grade of failure to (a student).
• intransitive verb To be detected by (a drug test) as having used a banned substance.
• noun A failing grade.
• idiom (without fail) With no chance of failure.

from The Century Dictionary.

• noun Lack; absence or cessation.
• noun Failure; deficiency: now only in the phrase without fail (which see, below).
• noun A failure, failing, or fault.
• noun A piece cut off from the rest of the sward; a turf; a sod.
• noun A woman's upper garment. Halliwell. See faille.
• To be or become deficient or lacking, as something expected or desired; fall short, cease, disappear, or be wanting, either wholly or partially; be insufficient or absent: as, the stream fails in summer; our supplies failed.
• To decline; sink; grow faint; become weaker.
• To come short or be wanting in action, detail, or result; disappoint or prove lacking in what is attempted, expected, desired, or approved: often followed by an infinitive or by of or in: as, he failed to come; the experiment failed of success; he fails in duty; the portrait fails in expression.
• To become unable to meet one's engagements, especially one's debts or business obligations; become insolvent or bankrupt.
• =Syn, 1. To fall short, come short, give out.
• To wane, fade, weaken.
• To come to naught, prove abortive.
• To break, suspend payment.
• To be wanting to; disappoint; desert; leave in the lurch.
• To omit; leave unbestowed or unperformed; neglect to keep or observe: as, to fail an appointment.
• To come short of; miss; lack.
• To deceive; delude; mislead.

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

• transitive verb To be wanting to ; to be insufficient for; to disappoint; to desert.
• transitive verb rare To miss of attaining; to lose.
• noun Miscarriage; failure; deficiency; fault; -- mostly superseded by failure or failing, except in the phrase without fail.
• noun obsolete Death; decease.
• intransitive verb To be wanting; to fall short; to be or become deficient in any measure or degree up to total absence; to cease to be furnished in the usual or expected manner, or to be altogether cut off from supply; to be lacking
• intransitive verb To be affected with want; to come short; to lack; to be deficient or unprovided; -- used with of.
• intransitive verb To fall away; to become diminished; to decline; to decay; to sink.
• intransitive verb To deteriorate in respect to vigor, activity, resources, etc.; to become weaker.
• intransitive verb obsolete To perish; to die; -- used of a person.
• intransitive verb To be found wanting with respect to an action or a duty to be performed, a result to be secured, etc.; to miss; not to fulfill expectation.
• intransitive verb To come short of a result or object aimed at or desired ; to be baffled or frusrated.
• intransitive verb To err in judgment; to be mistaken.
• intransitive verb To become unable to meet one's engagements; especially, to be unable to pay one's debts or discharge one's business obligation; to become bankrupt or insolvent.