Very thin, as thin as a wafer. / Extremely marginal or tenuous.

Both thickets and thin woodland; (through) all obstacles in a path. / (idiomatic) Both good and bad times.

(idiomatic) Overly sensitive to criticism; quick to take offence; irritable; touchy / Used other than figuratively or idiomatically: see thin, skinned.

(transitive) To make sparse; to remove some of a group of newly-planted plants in order to allow the remaining ones to grow unimpeded / (intransitive) To become sparse.

plural of thin section

(mineralogy) A thin, optically flat sliver of a material, especially a rock or mineral, that can be used in microscopy. / Used other than figuratively or idiomatically: see thin, section.

An approach to computing based around the use of thin clients.

(finance, stock market) The characteristic of lower trading frequency, commonly observed with lesser known companies and firms listed on the market. It often suggests higher level of investment opportunity and risk for investors, less transparency and less public information.

(idiomatic) In a dangerous, hazardous, or delicate situation; at risk.

(idiomatic) dangerously, hazardously, delicately