Hollowest

adjective

1. (of something solid) Having an empty space or cavity inside.

   "a hollow tree; a hollow sphere"

2. (of a sound) Distant, eerie; echoing, reverberating, as if in a hollow space; dull, muffled; often low-pitched.

   "He let out a hollow moan."

3. Without substance; having no real or significant worth; meaningless.

   "a hollow victory"

4. Insincere, devoid of validity; specious.

   "a hollow promise"

5. Concave; gaunt; sunken.