attacking cherished traditions, such as religion and traditional moral values
In an iconoclastic book on the nation's history, he dismissed many national heroes as scoundrels and fools.
eikon eikonos (likeness, image, portrait) (Greek)
icon = idol clash = fragments. So, one who destroys idols into pieces is iconoclast. ICONOCLASTIC -> ICON (idol) + CLASH. CLASHing/destroying IDOLS/traditions