Kaab (כָּאַב) means to experience physical or emotional pain — to be pained, grieved, hurt. The noun keeb (H3511) is pain itself. The word appears in both physical and deeply psychological contexts, including God's own grief.
One of Scripture's most staggering claims is that God grieves. Genesis 6:6 says the LORD was "grieved in his heart [yitatseb]" over human wickedness — a word parallel to kaab in meaning. Isaiah 63:9 declares, "In all their distress he too was distressed." God is not an impassive deity; He enters into kaab. Job's use of kaab legitimizes human lament: to acknowledge pain before God is not weakness but honesty. The suffering servant of Isaiah 53 is described as "a man of sorrows, acquainted with grief [machob]" — the same pain-root family.
Kaab sits in the semantic field with atsab (H6087, to grieve/hurt), yagon (H3015, sorrow), and anah (H6031, to be afflicted). The specificity of kaab is its emphasis on the felt quality of suffering — not just circumstantial trouble but the ache that registers in the body and soul. Theologically, a God who knows kaab can be a comfort to those who suffer: He does not advise from a distance.