The quality, state, or habit of being absentminded.(noun)
The Century Dictionary (Public Domain)
Use "absent-mindedness" in a sentence
"As Mr. Foer's own occasional absent-mindedness should remind us, the human memory is a complicated, confounding subject."
"Was it through a fit of absent-mindedness or gross incompetence?"
"You may be wondering why I don't write a few columns in advance, just in case of illness, natural disasters, hangovers or in this case absent-mindedness."