thin

verb

thinned; thinning

transitive verb

: to make thin or thinner:

a

: to reduce in thickness or depth : attenuate

b

: to make less dense or viscous

c

: dilute, weaken

d

: to cause to lose flesh

thinned by weeks of privation

e

: to reduce in number or bulk

intransitive verb

1

: to become thin or thinner

2

: to become weak

Synonyms of thin

• dilute
• cut
• dirty
• load

Examples of thin in a Sentence

He added a little more water to thin the gravy.

The haze thinned in the late afternoon.

His face has been thinned by illness.

Recent Examples on the Web

Clover tends to pop up in areas where the lawn is thinning or brown and attracts pollinators like bees. —David Beaulieu, The Spruce, 6 June 2026

The unit has been thinned by injuries to Eury Pérez, Janson Junk and Robby Snelling after entering the season with respectable depth, and manager Clayton McCullough has yet to find a pitcher who has consistently risen to the occasion. —Tyler Carmona, Miami Herald, 6 June 2026

For one, the event was sparsely attended, highlighting the dearth of foreign visitors and the thinning ranks of bankers, executives, and investors in the city. —Mohammed Sergie, semafor.com, 4 June 2026

Equipped with a sophisticated suite of instruments, the probe was designed to study the Martian atmosphere to learn more about how it is eroded, or blown away and thinned out by particles in the solar wind. —William Harwood, CBS News, 3 June 2026

Word History

Etymology

Middle English thinnen, going back to Old English þynnian, derivative of þynne thin entry 1

First Known Use

before the 12th century, in the meaning defined at transitive sense

Phrases Containing thin

• disappear/vanish into thin air
• have a thin time (of it)
• into thin air
• on thin ice
• out of thin air
• paper-thin
• razor-thin
• run thin
• the thin end of the wedge
• thick and thin
• thin film
• thin-layer chromatography
• thin on the ground
• thin skin
• thin-skinned
• thin smile
• through thick and thin
• wafer-thin
• wear thin

Rhymes for thin

• been
• bin
• chin
• din
• djinn
• fin
• finn
• gin
• grin
• in
• kin
• linn

Kids Definition

thin

1 of 2 adjective

ˈthin 

thinner; thinnest

1

: having little extent from one surface to its opposite

thin paper

2

: having widely scattered units

thin hair

3

: having too little flesh

a tall thin boy

4

: less dense than normal

thin air

5

: lacking substance or strength

thin broth

thin excuses

6

: somewhat weak or shrill

a thin voice

thinly adverb

thinness

ˈthin-nəs 

noun

thin

2 of 2 verb

thinned; thinning

1

: to make or become thin

2

: to reduce in number especially to prevent crowding

thin young carrots in the garden