Dryness, drought, parching heat, or desolation. This is the common noun (distinct from the proper noun Horeb/Sinai) describing the scorching, life-draining heat of the desert. It represents everything hostile to life — the opposite of God's living water and green pastures.
Choreb as drought is one of Scripture's key images of spiritual desolation. Jeremiah uses it to describe the curse on those who trust in human strength rather than God (Jeremiah 17:6). Yet God promises to turn even the choreb — the wasteland — into springs of water (Isaiah 35:7). The drought of the soul finds its answer in the living water Christ offers (John 4:14).