falter

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To be unsteady in purpose or action, as from loss of courage or confidence; waver. See Synonyms at hesitate.
2. v. To speak hesitatingly; stammer.
3. v. To move ineptly or haltingly; stumble.
4. v. To operate or perform unsteadily or with a loss of effectiveness: The automobile engine faltered.
5. n. Unsteadiness in speech or action.
6. n. A faltering sound.

Century Dictionary and Cyclopedia

1. To be unsteady; tremble; totter: as, his legs falter.
2. To fail in accuracy, distinctness, or regularity of exercise or function; fail or waver from physical or moral weakness, emotion, etc.
3. To hesitate, especially to hesitate in the utterance of words; speak with a broken or trembling utterance; stammer: as, his tongue falters.
4. Synonyms Stutter, etc. See stammer.
5. n. The act of faltering, hesitating, trembling, stammering, or the like; unsteadiness; hesitation; trembling; quavering.
6. To thresh in the chaff; cleanse or sift out, as barley.

Wiktionary

1. n. unsteadiness.
2. v. To waver or be unsteady.
3. v. To stammer.
4. v. To stumble.
5. v. figuratively To lose faith or vigor; to doubt or abandon (a cause).

GNU Webster's 1913

1. v. Prov. Eng. To thrash in the chaff; also, to cleanse or sift, as barley.
2. v. To hesitate; to speak brokenly or weakly; to stammer.
3. v. To tremble; to totter; to be unsteady.
4. v. To hesitate in purpose or action.
5. v. To fail in distinctness or regularity of exercise; -- said of the mind or of thought.
6. v. To utter with hesitation, or in a broken, trembling, or weak manner.
7. n. Hesitation; trembling; feebleness; an uncertain or broken sound.

WordNet 3.0

1. v. walk unsteadily
2. n. the act of pausing uncertainly
3. v. speak haltingly
4. v. be unsure or weak
5. v. move hesitatingly, as if about to give way