- check in
Intransitive
Meaning: arrive and register at a hotel or airport
Example: We will get the hotel keys when we check in.
check out
Intransitive
Meaning: leave a hotel
Example: Most hotels require you to check out before 1pm.
check out someone/something
Transitive, Separable
Meaning: look at informally
Example: Check out these boots! I want a pair.
That guy over there just checked you out!