- busy, engaged, in use - (of facilities such as telephones or lavatories) unavailable for use by anyone else or indicating unavailability; (`engaged' is a British term for a busy telephone line); "her line is busy"; "receptionists' telephones are always engaged"; "the lavatory is in use"; "kept getting a busy signal"
Antonym: unoccupied (indirect, via occupied)
- in use - currently being used; "robots are in use throughout industry"
Antonym: misused (indirect, via used)