oblivious
unaware / unmindful / heedless
Adjective
This term describes a state of total unawareness, often implying a lack of attention or a mental detachment from the immediate environment. It carries a nuance of innocence or negligence, suggesting that the person is not merely ignoring the facts but is completely blind to them. While it can describe a temporary lapse in concentration, it frequently characterizes a personality trait or a specific psychological state where an individual is absorbed in their own thoughts to the exclusion of external reality.