'anti-opium' is a compound of the prefix 'anti-' and the noun 'opium'. 'Anti-' originates from Greek 'antí' meaning 'against', and 'opium' comes from Latin 'opium' via Greek 'ὄπιον (opion)' meaning 'poppy juice'.

'anti-' (Greek) + 'opium' (Latin/Greek) combined in modern English to form the compound 'anti-opium', especially used in contexts such as 19th–20th century public health and policy (e.g., anti-opium campaigns).

Initially simply a literal compound meaning 'against opium'; over time it has been used as both an adjective describing opposition to opium and as a noun referring to movements or actors opposing opium.