senile /ˈsiːnaɪl/adjective 2noun 1forms 3 adjective2 •Of, or relating to old age. •(offensive) Exhibiting the deterioration in mind and body often accompanying old age; doddering.Her mother was senile, but they called it dementia now. — 2019 noun1 •(old-fashioned) A person who is senile.Seniles differ markedly in their early adult intelligence level, and in their social, vocational, and educational histories. — 1979 formsseniles · more senile · most senile