› working hard, or giving your attention to a particular thing: too busy to do sth I have been far too busy to think about taking time off.busy with sth/sb All our agents are currently busy with other customers.busy doing sth While we were busy planning our expansion, he was planning to take over the company.a busy man/woman/person I won't take up much of your time, because I know you're a busy woman.
› full of activity or people: a busy office/restaurant/street The shop is always busy on Saturdays.
› in a busy period, you have a lot of things to do: a busy week/day/morning It’s been a busy week.
› (UK also engaged) COMMUNICATIONS if a telephone line is busy, someone is using it: I tried calling the office, but the line was busy.