From Longman Dictionary of Contemporary Englishasphyxiateas‧phyx‧i‧ate /æsˈfɪksieɪt, əs-/ verb [intransitive, transitive] formal MIto prevent someone from breathing normally, usually so that they die, or stop breathing SYN suffocate —asphyxiation /æsˌfɪksiˈeɪʃən, əs-/ noun [uncountable]→ See Verb table
Examples from the Corpus
asphyxiate• Maybe she was hoping to asphyxiate him with carbon monoxide fumes.• And I suppose we'd better go and asphyxiate ourselves up at the sulphur springs.• Sulphur hexafluoride itself is harmless except in a confined space, where it displaces oxygen and can asphyxiate people. 