cavernous, hole, excavate, dig, reverberant, hollow out, deep-set, recessed, cannular, sunken, more...

solid, filled, substantial, dense, compact

tube, pipe, channel, cavity, pore, duct, vein, artery, capillary, more...

little, deep, small, slight, large, more, shaped, sound, dark, natural, shallow

feeling empty,   empty eyes,   sunken eyes,   empty inside,   anatomical cavity,   feel empty,   empty on the inside,   when you feel empty,   hole in tree trunk,   sunken cheek