1. A low level of attention or an intense attention to a single object of focus that makes a person unaware of what is going on around him or her: Absentmindedness is clearly a part of everyone's life when something is merely inconvenient, such as missing a familiar turnoff on the highway, or some are very serious as when absentmindedness can cause accidents, injury, or even a loss of life.

Jeff's absentmindedness caused him to be late because he took the wrong public transportation to work.

2. A preoccupation with something that is so great that the ordinary demands of attention on something else are ignored: Cheryl was so lost in her absentmindedness that she was unaware of where she was or what she was supposed to be doing there.