1.Definition: (of sound) lacking resonance or volume
"A thin feeble cry"
2.Definition: lacking excess flesh
"You can't be too rich or too thin"
3.Definition: lacking spirit or sincere effort
"A thin smile"
4.Definition: lacking substance or significance
"A thin plot"
5.Definition: not dense
"A thin beard"
6.Definition: of relatively small extent from one surface to the opposite or in cross section
"Thin wire", "A thin chiffon blouse", "A thin book", "A thin layer of paint"
7.Definition: relatively thin in consistency or low in density; not viscous
"Air is thin at high altitudes", "A thin soup", "Skimmed milk is much thinner than whole milk", "Thin oil"
8.Definition: very narrow
"A thin line across the page"