achromatopsia
/ˌeɪkrəʊməˈtɒpsɪə/ /əkrəʊməˈtɒpsɪə/(also achromatopsy) Medicine
noun
Inability to distinguish between some or (usually) all colours; absence, severe impairment, or loss of colour vision; colour blindness, especially monochromatism.
Origin
Mid 19th century; earliest use found in The Lancet. From German Achromatopsie, †Achromatopsia from ancient Greek ἀχρώματος + Hellenistic Greek -οψία.