oblivious

adjective

unaware or unmindful of

Wiktionary

Pronunciation: /əˈblɪviːəs/

adj

Etymology: From Middle English oblivious, from Latin oblīviōsus (“forgetful, oblivious”), formed from oblīvium (“forgetfulness, oblivion”) + -ōsus (“full of, overly, prone to”), from oblīvīscor (“to forget”).

Lacking awareness; unmindful; unaware, unconscious of.
“Your grandmother is completely oblivious to her surroundings.”
Forgetful.
“He's hopelessly oblivious, always forgetting his appointments.”