'antiknock' originates from English, formed as a compound of the prefix 'anti-' (from Greek 'anti', where 'anti-' meant 'against') and the English word 'knock' (originally from Old English 'cnocian', where 'cnocian' meant 'to strike').

'antiknock' developed in the early 20th century as internal combustion engine technology emerged; the compound combined 'anti-' + 'knock' to name substances or qualities that act 'against' engine 'knocking', and it became common in technical and commercial contexts by the mid-20th century.

Initially it literally meant 'against knock' (i.e., acting to prevent knocking); over time it retained this technical sense and is now used specifically for additives or properties that reduce engine detonation.