Answer: occupied

AnswerCrossword Clue
OCCUPIEDBusy
OCCUPIEDIn use
OCCUPIEDJohn sign
occupied(of a building, seat, etc.) Being used by someone
occupiedBusy and active
occupied(of a place, esp. a country) Taken control of by military conquest or settlement
occupiedOCCUPY, to reside in, also OCCUPATE