IPA: /ˈæntɪˌsmoʊkər/
KK: /ˈæntiˌsmoʊkər/
A person who is against smoking, especially tobacco use.
The antismoker campaign aimed to reduce tobacco use in public places.
Antismoker → It is formed from "anti-" (meaning against) and "smoker" (from the verb "smoke", which has origins in Old English "smocian", meaning to emit smoke). The word "antismoker" refers to someone who is against smoking or opposes the act of smoking.
Think of being 'against' ('anti-') someone who 'smokes' — that's why an antismoker is someone who opposes smoking.
No commonly confused words.