Adjective: antiknock ,an-tee'nók
- Suppressing or eliminating engine knock in combustion engines
"antiknock rating";
- antiknocking
- Any of various compounds that are added to petrol to reduce engine knocking
"Tetraethyl lead was once a common antiknock additive in petrol"
Derived forms: antiknocks
See also: leaded
Type of: chemical compound, compound