Internecine (?), a. [L. internecinus deadly, murderous, fr. internecare to kill, to slaughter; inter between + necare to kill; akin to Gr. &unr_; dead. See Necromancy.] 1. Involving, or accompanied by, mutual slaughter; mutually destructive.
[1913 Webster]

Internecine quarrels, horrible tumults, stain the streets with blood. Motley.
[1913 Webster]

2. Of or pertaining to internal conflicts within a group; as, internecine quarrels.
Syn. -- intramural.
[PJC]