This vivid adjective literally means 'double-souled' or having two minds, describing someone unstable or wavering in their commitments. James uses it twice: calling the double-minded man unstable in all his ways (1:8), and urging sinners to purify their hearts since they are 'double-minded' (4:8). The term captures internal division and consequent instability—trying to serve two masters or hold conflicting loyalties. The 'di-psychos' construction suggests a soul split between competing allegiances. Spanish 'de doble ánimo' (of double spirit) and German 'zweifelhaft' (doubtful) attempt to capture this internal division that produces unreliability and instability in all behavior.