IPA: /ˌætəˈvɪstɪk/
KK: /ˌætəˈvɪstɪk/
Relating to something that is primitive or a throwback to an earlier stage of development.
The atavistic instincts of survival can sometimes emerge in modern humans during times of crisis.
Atavistic is formed from "atavus" (meaning ancestor) and the suffix "-istic" (meaning pertaining to). The word describes something that relates to or is characteristic of an ancestor or ancestral traits.
Think of 'ancestor' ('atavus') to remember that 'atavistic' refers to traits or characteristics that come from ancestors.