From qashar; an (unlawful) alliance -- confederacy, conspiracy, treason.
see HEBREW qashar
H7195. qesher
קֶ֫שֶׁר noun masculine2 Samuel 15:12 conspiracy; — absolute ׳ק 15:12 +, קָ֑שֶׁר 2 Kings 11:14 +; construct קֶ֫שֶׁר Ezekiel 22:25 (but see below); suffix קִשְׁרוֺ 1 Kings 16:20; 2 Kings 15:15; — conspiracy 2 Samuel 15:12; as accusative of congnate meaning with verb with קָשַׁר 1 Kings 16:20; 2 Kings 12:21; 14:19 2 Chronicles 25:27; 2 Kings 15:15, 30; ק ׳בְּהוֺשֵׁעַ וַיִּמְצָא 17:4, ק ׳נִמְצָא וגו ׳בְּאִישׁ Jeremiah 11:9; as exclamation 2 Kings 11:14 (twice in verse) = 2 Chronicles 23:13 (twice in verse), Isaiah 8:12 (twice in verse) (Gr Lag CheComm. GuKau and others קֹדֶשׁ or קָדשׁ); נְבִיאֶיהָ Ezekiel 22:35, < read נְשִׂיאֶיהָ Co Toy Krae and others (after ᵐ5).