worry

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

• intransitive verb To feel uneasy or concerned about something; be troubled. synonym: brood.
• intransitive verb To seize something with the teeth and bite or tear repeatedly.
• intransitive verb To touch or handle something nervously or persistently.
• intransitive verb To attempt to deal with something in a persistent or dogged manner.
• intransitive verb To cause to feel anxious, distressed, or troubled. synonym: trouble.
• intransitive verb To seize with the teeth and bite or tug at repeatedly.
• intransitive verb To touch or handle nervously or persistently.
• intransitive verb To attack roughly and repeatedly; harass.
• intransitive verb To bother or annoy, as with petty complaints.
• intransitive verb To attempt to deal with in a persistent or repeated manner.
• intransitive verb To chase and nip at or attack.
• noun The act of worrying or the condition of being worried; persistent mental uneasiness.
• noun A source of nagging concern or uneasiness.
• idiom (not to worry) There is nothing to worry about; there is no need to be concerned.

from The Century Dictionary.

• To choke; suffocate.
• To seize by the throat with the teeth; bite at or tear with the teeth, as dogs when fighting; kill or injure badly by repeated biting, tearing, shaking, etc.: as, a dog that worries sheep; a terrier worries rats.
• To tease; trouble; harass with importunity or with care and anxiety; plague; bother; vex; persecute.
• Synonyms Pester, Plague, etc. (see tease), disturb, disquiet.
• To choke; be suffocated, as by something stopping the windpipe.
• To fight, as dogs, by seizing and biting at each other; be engaged in biting, shaking, or mangling with the teeth.
• To be unduly anxious and careful; give way to anxiety; be over-solicitous or disquieted about things; borrow trouble; fret.
• noun The act of worrying or biting and mangling with the teeth; the act of killing by biting and shaking.
• noun Harassing anxiety, solicitude, or turmoil; perplexity arising from over-anxiety or petty annoyances and cares; trouble: as, it is not work but worry that kills; the worries of housekeeping.

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

• intransitive verb To feel or express undue care and anxiety; to manifest disquietude or pain; to be fretful; to chafe
• noun A state of undue solicitude; a state of disturbance from care and anxiety; vexation; anxiety; fret.
• transitive verb To harass by pursuit and barking; to attack repeatedly; also, to tear or mangle with the teeth.
• transitive verb To harass or beset with importunity, or with care an anxiety; to vex; to annoy; to torment; to tease; to fret; to trouble; to plague.
• transitive verb colloq. To harass with labor; to fatigue.

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

• verb transitive To seize or shake by the throat, especially of a dog or wolf.
• verb transitive To harass; to irritate or distress.
• verb transitive Disturb the peace of mind of; afflict with mental agitation or distress.
• verb intransitive To be troubled, to give way to mental anxiety.
• verb transitive, obsolete, except in Scots To strangle.
• noun A strong feeling of anxiety.
• noun An instance or cause of such a feeling.

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

• verb touch or rub constantly
• verb lacerate by biting
• verb disturb the peace of mind of; afflict with mental agitation or distress
• noun something or someone that causes anxiety; a source of unhappiness
• verb be concerned with
• verb be worried, concerned, anxious, troubled, or uneasy
• noun a strong feeling of anxiety
• verb be on the mind of