A clash or disagreement, often violent, between two or more opposing groups or individuals.
An incompatibility, as of two things that cannot be simultaneously fulfilled.
To overlap (with), as in a schedule.
To be at odds (with); to disagree or be incompatible
A bitter, destructive feud, normally between two families, clans, or factions, in which each injury or slaying is revenged: a blood feud.
Revenge.
A motivational grudge against a person or faction, which may or may not be reciprocated; the state of having it in for someone.