'antiaristocratical' originates from the prefix 'anti-' (from Greek 'anti-' meaning 'against') combined with 'aristocratical' (from 'aristocrat' + suffix '-ical'), where 'aristocrat' derives from Greek 'aristokratia' meaning 'rule of the best'.

'aristokratia' (Greek) → Latin/Medieval Latin 'aristocratia' → French 'aristocratique' / English 'aristocratical', to which the productive prefix 'anti-' was attached in English to form 'antiaristocratical'.

Initially related to opposition to the idea or rule of an 'aristocracy' ('rule of the best'), it came to be used simply to describe attitudes, policies, or rhetoric that are opposed to aristocrats or aristocratic influence.