'anti-ritualistic' is a modern English compound formed from the prefix 'anti-' (from Greek 'anti' meaning 'against') + 'ritualistic' (related to 'ritual').

'ritualistic' comes from English 'ritual' which derives from Latin 'ritualis' (from 'ritus' meaning 'rite'); 'anti-' comes from Greek 'anti' meaning 'against'; the compound 'anti-ritualistic' is formed in modern English by combining these elements to mean 'against ritual/ritualism'.

Originally the parts meant 'against' + 'pertaining to rites'; over time the compound has come to mean specifically 'opposed to ritualism or formalized ceremonial practice' in modern usage.