stumble

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To miss one's step in walking or running; trip and almost fall.
2. v. To proceed unsteadily or falteringly; flounder. See Synonyms at blunder.
3. v. To act or speak falteringly or clumsily.
4. v. To make a mistake; blunder.
5. v. To fall into evil ways; err.
6. v. To come upon accidentally or unexpectedly: "The urge to wider voyages . . . caused men to stumble upon New America” ( Kenneth Cragg).
7. v. To cause to stumble.
8. n. The act of stumbling.
9. n. A mistake or blunder.

Century Dictionary and Cyclopedia

1. To slip or trip in moving on the feet; make a false step; strike the foot, or miss footing, so as to stagger or fall.
2. To move or act unsteadily or in a staggering manner; trip in doing or saying anything; make false steps or blunders, as from confusion or inattention: as, to stumble through a performance.
3. To take a false step or be staggered mentally or morally; trip, as against a stumbling-block; find an occasion of offense; be offended or tempted.
4. To come accidentally or unexpectedly; chance; happen; light: with on or upon.
5. To cause to stumble; cause to trip; stagger; trip up.
6. To puzzle; perplex; embarrass; nonplus; confound.
7. n. The act of stumbling; a trip in walking or running.
8. n. A blunder; a failure; a false step.

Wiktionary

1. n. a fall, trip or substantial misstep
2. n. an error or blunder
3. v. intransitive to trip or fall
4. v. intransitive to make a mistake or have trouble

GNU Webster's 1913

1. v. To trip in walking or in moving in any way with the legs; to strike the foot so as to fall, or to endanger a fall; to stagger because of a false step.
2. v. To walk in an unsteady or clumsy manner.
3. v. To fall into a crime or an error; to err.
4. v. To strike or happen (upon a person or thing) without design; to fall or light by chance; -- with on, upon, or against.
5. v. To cause to stumble or trip.
6. v. Fig.: To mislead; to confound; to perplex; to cause to err or to fall.
7. n. A trip in walking or running.
8. n. A blunder; a failure; a fall from rectitude.

WordNet 3.0

1. v. miss a step and fall or nearly fall
2. n. an unintentional but embarrassing blunder
3. v. walk unsteadily
4. v. encounter by chance
5. v. make an error
6. n. an unsteady uneven gait