Noun

1. Lack of attention and due care
2. The state of something that has been unused and neglected
3. Willful lack of care and attention
4. The trait of neglecting responsibilities and lacking concern
5. Failure to act with the prudence that a reasonable person would exercise under the same circumstances

Verb

1. Leave undone or leave out
2. Fail to do something; leave something undone
3. Fail to attend to
4. Give little or no attention to