'antispasmodic' originates from a Modern English formation combining the prefix 'anti-' (from Greek 'anti' meaning 'against') and 'spasmodic' (from Late Latin/Greek 'spasmos' meaning 'a convulsion').

'spasmodic' comes via Late Latin 'spasmodicus' from Greek 'spasmos' ('a convulsion'), and the modern English compound 'antispasmodic' was formed by adding the prefix 'anti-' to 'spasmodic' in post-medieval English usage (17th–18th century onward).

Initially it meant 'against or opposing spasms' in a general sense; over time it became a standard medical term referring specifically to drugs or agents that reduce or prevent muscle spasms.