internecineyoudaoicibaDictYouDict[internecine 词源字典]
internecine: [17] Etymologically, internecine denotes ‘attended by great slaughter’. Its modern connotations of ‘conflict within a group’, which can be traced back to the 18th century (Dr Johnson in his Dictionary 1755 defines it as ‘endeavouring mutual destruction’), presumably arise from the standard interpretation of inter- as ‘among, between’. But in fact in the case of internecine it was originally used simply as an intensive prefix.

The word was borrowed from Latin internecīnus, a derivative of internecāre ‘slaughter, exterminate’. This was a compound verb formed with the intensive inter- from necāre ‘kill’ (a relative of English necromancy and pernicious).

=> necromancy, pernicious[internecine etymology, internecine origin, 英语词源]
internecine (adj.)youdaoicibaDictYouDict
1660s, "deadly, destructive," from Latin internecinus "very deadly, murderous, destructive," from internecare "kill or destroy," from inter (see inter-) + necare "kill" (see noxious). Considered in the OED as misinterpreted in Johnson's Dictionary [1755], which defined it as "endeavouring mutual destruction," on association of inter- with "mutual" when the prefix supposedly is used in this case as an intensive. From Johnson, wrongly or not, has come the main modern definition of "mutually destructive."
Internet (n.)youdaoicibaDictYouDict
1985, "the linked computer networks of the U.S. Defense Department," shortened from internetwork, from inter- + network (n.).
interneuronyoudaoicibaDictYouDict
1939, from internuncial + neuron.
internecinalyoudaoicibaDictYouDict
"= internecine", Early 19th cent.; earliest use found in The Times. From classical Latin internecīnus internecine + -al.