1) Abandoned 2) Deserted 3) Desolate 4) Empty 5) Forsaken 6) Free 7) Idle 8) Isolated 9) Not busy or active 10) Not held or filled or in use 11) Not seized and controlled 12) Spare 13) Unpopulated 14) Vacant 15) Without inhabitants 16) Without occupants Found on https://www.crosswordclues.com/clue/unoccupied
without occupants; empty; vacant. · not held or controlled by invading forces: unoccupied nations. · not busy or active; idle; not gainfully employed: an unoccupied person. · without inhabitants; deserted. Found on https://www.infoplease.com/dictionary/unoccupied