'anticynicism' originates from Modern English, specifically the combination of the prefix 'anti-' (from Greek via Latin meaning 'against') and the noun 'cynicism' (meaning a cynical attitude).

'anticynicism' is a modern coinage formed by attaching 'anti-' to 'cynicism'; 'cynicism' itself comes from French 'cynisme' and Latin 'cynicus', which in turn comes from Greek 'kynikos' (κυ̂νικος) meaning 'dog-like' or belonging to the Cynic school.

Initially, 'kynikos' referred to the ancient Greek philosophical school (literally 'dog-like'); over time 'cynicism' shifted toward a general attitude of distrust or contempt for motives, and 'anti-' retained its sense 'against', so 'anticynicism' evolved to mean opposition to that distrust—an affirmation of trust or sincerity.