no-smoking (adj.) Look up no-smoking at Dictionary.com
1905; the sign wording itself is attested by 1817.
Smoking is a vice to [sic] -- and a national one, of such magnitude that railroad corporations throughout all their routes in the United States, have a special command in large letters, conspicuously placed at depots and inside of the cars -- "No smoking allowed here." ["The Sailor's Magazine," December 1840]