animosity

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

• noun Bitter hostility or open enmity; active hatred. synonym: enmity.
• noun A hostile feeling or act.

from The Century Dictionary.

• noun Animation; courage; spiritedness.
• noun Active enmity; hatred or ill-will which manifests itself in active opposition.
• noun Synonyms Animosity, Ill-will, Enmity, Malice, Hostility, Hatred, Hate, Malevolence, Malignity, Rancor, Grudge, Spite. These words differ from those described under acrimony, anger, and antipathy (which see) in that they represent deeper feelings or more permanent passions. Ill-will may represent the minimum of feeling, being a willing or wishing of ill to another, generally without disposition to be active in bringing the evil about. Enmity is a somewhat stronger feeling, and it often gratifies itself in trifling and cowardly ways. Animosity is more intense than enmity; it is avowed and active, and what it does is more serious than the covert attacks of enmity or the hasty attacks of spite. Malice is pure badness of heart, delighting in harm to others for its own sake. Hostility is less passionate than animosity, but not less avowed or active, being a state of mind inclining one to aggressive warfare. Hatred and hate are the general words to cover all these feelings; they may also be ultimate, expressing the concentration of the whole nature in an intense ill-will. Malevolence is more casual and temporary than malice, arising upon occasion furnished, and characterized by a wish that evil may befall another rather than by an intention to injure. Malignity is malice intensified; it is hatred in its aspect of destructiveness or desire to strike at the most vital interests of another. Rancor is hatred or malice turned sour or bitter; it is implacable in its vindictiveness. A grudge is a feeling of sullen ill-will or enmity, caused by a trifling wrong, and likely to be appeased when it has spent itself in a similar return against the offender. Spite is sudden, resentful, and generally quite as well pleased to mortify as to damage another; it may be as strong as malice or as weak as pique.
• noun In Spinoza's philosophy, the desire by which each man endeavors to preserve his own being after the guidance of reason alone; or, as sometimes interpreted, the steadfast and intelligent purpose to promote one's own welfare.

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

• noun obsolete Mere spiritedness or courage.
• noun Violent hatred leading to active opposition; active enmity; energetic dislike.

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

• noun Violent hatred leading to active opposition; active enmity; energetic dislike.

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

• noun a feeling of ill will arousing active hostility