* Out of it: They might be absentminded, forgetful, or seem to be in a daze.
* Unfocused: They lack concentration and may struggle to pay attention.
* Weird or eccentric: They might have unusual habits, beliefs, or interests.
* Under the influence of drugs: This is a less common meaning but can be used to describe someone who is high.
Examples:
* "My roommate is such a space case; he forgets where he puts his keys every day."
* "She's a bit of a space case, but she's also really creative."
* "Don't ask him anything right now; he's a total space case."
The term "space case" is generally used in a humorous or lighthearted way, but it can also be used to be slightly critical or mocking.