having relatively little extent from one surface or side to the opposite; not thick

thin ice.

of small cross section in comparison with the length; slender

a thin wire.

having little flesh; spare; lean

a thin man.

composed of or containing objects, particles, etc., widely separated; sparse

thin vegetation.

scant; not abundant or plentiful.

of relatively slight consistency or viscosity

thin soup.

rarefied, as air.

without solidity or substance; flimsy

a very thin plot for such a long book.

lacking fullness or volume; weak and shrill

a thin voice.

without force or a sincere effort

a thin smile.

lacking body, richness, or strength

a thin wine.

lacking in chroma; of light tint.

Photography . (of a developed negative) lacking in density or contrast through underdevelopment or underexposure.

in a thin manner.

sparsely; not densely.

so as to produce something thin

Slice the ham thin.

to make thin or thinner (often fol. by down, out, etc.).

to become thin or thinner; become reduced or diminished (often fol. by down, out, off, etc.)

The crowd is thinning out.

adjective

dense , fat , heavy , inflated , obese , thick , solid , efficient , strong , concentrated , undiluted

verb

beef up , thicken

adjective

attenuate , attenuated , beanpole * , beanstalk , bony * , cadaverous , delicate , emaciated , ethereal , featherweight , fragile , gangling , gangly , gaunt , haggard , lank , lanky , lean , lightweight , meager , narrow , peaked , pinched , pole * , puny * , rangy , rarefied , rawboned , reedy , rickety , scraggy , scrawny , shadow , shriveled , skeletal , skinny , slight , slim , slinky , small , spare , spindly , stalky , starved , stick * , stilt , subtle , threadlike , twiggy , twiglike , undernourished , underweight , wan , wasted , wizened , diaphanous , filmy , flimsy , gossamer , paper-thin , permeable , rare , refined , see-through , sheer , subtile , tenuous , translucent , unsubstantial , wafer-thin , wispy , diluted , feeble * , flat * , flimsy * , implausible , improbable , inadequate , inconceivable , incredible , insubstantial , insufficient , lame , poor , questionable , scant , scanty , scarce , scattered , shallow , sketchy , skimpy * , sparse , stretched , superficial , thick * , transparent , unbelievable , unconvincing , unpersuasive , untenable , vapid , weak-kneed , diffuse , dilute , dispersed , fine , light , runny , watery , weak , wishy-washy * , angular , bony , fleshless , slender , weedy , washy , watered-down , waterish , exiguous , puny , skimpy , stingy , shaky , unconceivable , chiffon , gauzy , gossamery , gracile , ichorous , incompact , malnourished , sleazy , stringy , svelte , tapering , wiry

verb

attenuate , cook , cut , cut back , decrease , delete , diminish , disperse , doctor , edit , emaciate , expand , extenuate , irrigate , lace * , needle * , prune , rarefy , reduce , refine , shave , spike , trim , water , water down , weaken , weed out , slim , acute , anorexic , beanpole , bony , dilute , emaciated , faint , fine , flimsy , gangly , gaunt , gossamer , hollow , inadequate , insufficient , lank , lanky , lean , meager , narrow , pale , poor , rare , rarefied , reedy , scant , scanty , scarce , scrawny , sheer , skeletal , skimpy , skinny , slender , slight , spare , sparse , stringy , subtilize , tenuous , transparent , twiggy , unconvincing , unsubstantial , watery , weak , wiry