IPA: /ˌæntiˈsmoʊkɪŋ/
KK: /æntiˈsmoʊkɪŋ/
Opposed to or preventing the use of tobacco, particularly in public places.
The city implemented an antismoking ordinance to protect public health.
Antismoking → It is formed from "anti-" (meaning against) and "smoking" (from the verb "smoke", which comes from Old English "smocian", meaning to emit smoke). The word "antismoking" means being against smoking or the act of smoking.
Think of being 'against' ('anti-') the act of 'smoking' — that's what antismoking means.