If you wait up, you deliberately do not go to bed, especially because you are expecting someone to return home late at night. I hope he doesn't expect you to wait up for him Don't wait up. = stay up
If you ask someone to wait up, you are asking them to go more slowly or to stop and wait for you. I was running down the hill shouting, `Michael, Michael, man, wait up'. = wait
wait up (for someone) birini yatmayıp beklemek
Silbentrennung
wa·it up (for so·me·o·ne) bi·ri·ni yat·ma·yıp bek·le·mek