Strife, contention, great effort.
A contortion of the body in an attempt to escape or to perform a difficult task.
To strive, to labour in difficulty, to fight (for or against), to contend.
To strive, or to make efforts, with a twisting, or with contortions of the body.
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.