It literally translates to "with sleep", but it's used to describe the state of being tired and wanting to sleep.
Here are some examples:
* "Estoy con sueño." (I am sleepy.)
* "Me siento con sueño." (I feel sleepy.)
* "El bebé está con sueño." (The baby is sleepy.)
It's important to note that "con sueño" is not always used in the same way as "sleepy" in English. Sometimes it can be used to describe a person who is simply tired, even if they're not actually feeling sleepy.