Pronunciation: (in"kō-hēr'unt, -her'-),[key] —adj. 1. without logical or meaningful connection; disjointed; rambling: an incoherent sentence. 2. characterized by such thought or language, as a person: incoherent with rage. 3. not coherent or cohering: an incoherent mixture. 4. lacking physical cohesion; loose: incoherent dust. 5. lacking unity or harmony of elements: an incoherent public. 6. lacking congruity of parts; uncoordinated.
7. different or incompatible by nature, as things.
8. Physics.(of a wave) having a low degree of coherence. Cf. coherent (def. 4).