Thinnest

adjective

1. Having little thickness or extent from one surface to its opposite.

   "thin plate of metal;  thin paper;  thin board;  thin covering"

2. Very narrow in all diameters; having a cross section that is small in all directions.

   "thin wire;  thin string"

3. Having little body fat or flesh; slim; slender; lean; gaunt.

   "thin person"

4. Of low viscosity or low specific gravity.

   "Water is thinner than honey."

5. Scarce; not close, crowded, or numerous; not filling the space.

   "The trees of a forest are thin; the corn or grass is thin."