Definitions of thin:

• verb:   make thin or thinner

  Example: "Thin the solution"

• verb:   lose thickness; become thin or thinner
• verb:   lessen the strength or flavor of a solution or mixture
• verb:   take off weight
• adjective:   (of sound) lacking resonance or volume

  Example: "A thin feeble cry"

• adjective:   lacking spirit or sincere effort

  Example: "A thin smile"

• adjective:   of relatively small extent from one surface to the opposite or in cross section

  Example: "Thin wire"

• adjective:   relatively thin in consistency or low in density; not viscous

  Example: "Air is thin at high altitudes"

• adjective:   lacking excess flesh

  Example: "You can't be too rich or too thin"

• adjective:   very narrow

  Example: "A thin line across the page"

• adjective:   not dense

  Example: "A thin beard"

• adjective:   having little substance or significance

  Example: "A thin plot"

• adverb:   without viscosity

  Example: "The blood was flowing thin"