adjective
busier; -est
[also more ~; most ~]
actively doing something
full of activity or work
full of people or things
chiefly US of a telephone or telephone line :being used
When you dial a telephone line that is already in use, you hear a sound that is called a busy signal.
full of many details
get busy
to start doing work
verb
busies; busied; busying
busy yourself
to make or keep yourself busy :to occupy (yourself) with work or an activity