Animosity, n.; pl. Animosities.
Etymology: [F. animosité, fr. L. animositas. See Animose, Animate, v. t.]
1. Mere spiritedness or courage. [Obs.] Skelton. Such as give some proof of animosity, audacity, and execution, those she [the crocodile] loveth. Holland.
2. Violent hatred leading to active opposition; active enmity; energetic dislike. Macaulay.
Syn. -- Enmity; hatred; opposition. -- Animosity, Enmity. Enmity be dormant or concealed; animosity is active enmity, inflamed by collision and mutual injury between opposing parties. The animosities which were continually springing up among the clans in Scotland kept that kingdom in a state of turmoil and bloodshed for successive ages. The animosities which have been engendered among Christian sects have always been the reproach of the church. Such [writings] as naturally conduce to inflame hatreds and make enmities irreconcilable. Spectator. [These] factions . . . never suspended their animosities till they ruined that unhappy government. Hume.
Shades of meaning
Fernald has no entry of its own for animosity; he lists it under anger, enmity, feud, hatred.
Where he writes about it:
Animosity denotes a feeling more active and vehement, but often less enduring and determined, than enmity. — from enmity