Out of it Definition 1 of 3Pro Tip 1/3Context Helps Check surrounding words to see if 'out of it' means tired or under the influence. After the night shift, he seemed really out of it. Pro Tip 2/3Impaired State Use when someone is not fully alert due to exhaustion, sickness, or substance use. With the cold medication, she was totally out of it. Pro Tip 3/3Not for Seriousness Better for casual conversation, may sound insensitive in serious situations. He's been out of it since the bad news.