Definition of “busy” - Learner’s Dictionary

busy

adjective uk us /ˈbɪzi/
PERSON

A2 If you are busy, you are working hard, or giving your attention to a particular activity:

Mum was busy in the kitchen.
[ + doing sth ] I was busy mowing the lawn.
There'll be plenty of jobs to keep you busy.
He was too busy talking to notice us come in.
PLACE

A2 A busy place is full of activity or people:

TIME

A2 In a busy period you have a lot of things to do:

I've had a very busy week.
TELEPHONE US (UK engaged)

If a telephone line is busy, someone is using it.

(Definition of “busy adjective” from the Cambridge Learner's Dictionary © Cambridge University Press)