Learn how to say Internecine correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word internecine:
destructive to both sides in a conflict:
the region’s history of savage internecine warfare
relating to conflict within a group:
the party shrank from the trauma of more internecine strife
mid 17th century (in the sense ‘deadly, characterized by great slaughter’): from Latin internecinus, based on inter- ‘among’ + necare ‘to kill’