'antiradical' originates from Ancient Greek prefix 'anti-' (from Greek 'anti' ἀντί) and the English word 'radical', where 'anti-' meant 'against' and 'radical' comes from Latin 'radicalis' ultimately from 'radix' meaning 'root'.

'radical' came into English via Latin 'radicalis' (from 'radix' 'root') and later French; in the 19th century English combined the prefix 'anti-' with 'radical' to form 'antiradical' to describe opponents of radicalism, and 'antiradicals' developed as its plural.

Initially components referred to 'against the root' (from literal sense of 'radix'), but over time 'antiradical(s)' came to mean specifically 'opposed to radicals or radical political change' in modern usage.