The Hebrew word kaas functions both as a verb meaning to be angry, vexed, or provoked, and as a noun meaning anger or vexation. It is used of human emotional provocation and of God's response to Israel's idolatry. Related words include wrath and grief.
Israel repeatedly provoked God to kaas through idolatry — the Deuteronomic history uses this word to describe the cycle of covenant betrayal. But the term also describes human grief and inner turmoil. Hannah's 'vexation of soul' (1 Sam 1:16) and the futility described in Ecclesiastes reflect the existential weight of kaas. The remedy is found not in self-help but in turning back to God.