dawdler

/ˈdɔdələr/
noun
  1. A person who wastes time or moves slowly, especially when they should be doing something else.
    • My little brother is such a dawdler in the morning; it takes him forever to get ready.
    • Don't be a dawdler — we have a deadline to meet.
    • The teacher told the dawdler to hurry up and join the class.