The Greek adjective dipsuchos (G1374) literally means 'two-souled' — having a divided soul, wavering between two commitments, unstable because of inner contradiction. James used it to describe the person who doubts God while praying.
Dipsuchos is James's diagnosis of the person who asks God for wisdom but simultaneously doubts: 'Such a person is double-minded (dipsuchos) and unstable in all they do' (James 1:8). This is not intellectual uncertainty but volitional division — the heart pulled between trust in God and trust in the world. The opposite of dipsuchos is haplotes — the person fully committed to God, whole and undivided.