IPA: /eɪˈtɪpɪk/
KK: /eɪˈtɪpɪk/
Describing something that does not conform to the usual type or pattern; unusual or irregular.
The scientist discovered an atypic behavior in the experiment that was not expected.
Atypic → It is formed from "a-" (meaning not) and "typic" (from Greek "typos", meaning type or model). The word "atypic" means not typical or not conforming to a type.
Think of 'not' ('a-') and 'type' ('typic') to remember that 'atypic' refers to something that is not typical.