IPA: /nɒnˈfʌŋkʃənl/
KK: /nɑnˈfʌŋkʃənl/
Not working or not able to perform its intended function; ineffective or broken.
The old printer is nonfunctional and needs to be replaced.
Nonfunctional → It is formed from "non-" (meaning not) and "functional" (from Latin "functio", meaning performance or execution). The word "nonfunctional" means not performing or not serving a function.
Think of 'non-' meaning 'not' and 'functional' relating to 'performance' — so nonfunctional describes something that is not performing its intended role.