ill

adjective

ˈil 

worse ˈwərs  ; worst ˈwərst 

1

a comparative also iller; superlative also illest

(1)

: not in good health

staying home because I'm ill

also : nauseated

(2)

: not normal or sound

ill health

b

: causing suffering or distress

ill weather

subjected to ill treatment

2

: unfriendly, hostile

comments that caused some ill feelings

3

a

: not suited to circumstances or not to one's advantage : unlucky

an ill omen

b

: involving difficulty : hard

4

a

: attributing evil or an objectionable quality

held an ill opinion of his neighbors

b

: resulting from, accompanied by, or indicative of an evil or malevolent intention

ill deeds

c

chiefly Scotland : immoral, vicious

5

a

: not meeting an accepted standard

ill manners

b

archaic : notably unskillful or inefficient

Synonyms of ill

• sick

Examples of ill in a Sentence

That dog can eat almost anything with no ill effects.

They had been subjected to months of ill treatment.

Recent Examples on the Web

Eight people were ill across the three states as of June 4, according to the CDC. —Mary Walrath-Holdridge, USA Today, 8 June 2026

In 2014, a Kansas resident became ill with what is now called the Bourbon virus, also caused by the lone star tick with similar symptoms and treatment. —Sophie Lindberg, Kansas City Star, 8 June 2026

In April, Murekezi was ordered civilly committed as mentally ill. —Nick Ferraro, Twin Cities, 8 June 2026

In 1982 his first wife became ill and died at age 32. —Graham Womack, Sacbee.com, 7 June 2026

Word History

Etymology

Middle English, from Old Norse illr

First Known Use

12th century, in the meaning defined at sense 4c

Phrases Containing ill

• bad/ill feelings
• bode ill
• for good and for ill
• house of ill repute
• ill-advised
• ill afford
• ill-assorted
• ill at ease
• ill-begotten
• ill-being
• ill-boding
• ill-bred
• ill-conceived
• ill-considered
• ill-defined
• ill-disposed
• ill effects
• ill-equipped
• ill-fated
• ill-favored
• ill feeling/feelings
• ill-gotten
• ill-humored
• ill-informed
• ill-judged
• ill-mannered
• ill-natured
• ill repute
• ill-sorted
• ill-starred
• ill-suited
• ill-tempered
• ill-timed
• ill-treat
• ill-usage
• ill-use
• ill will
• ill-wisher
• physically ill
• terminally ill
• violently ill
• with bad/ill grace
• woman of ill repute

Rhymes for ill

• bill
• brill
• chill
• drill
• fil
• fill
• frill
• gill
• grill
• grille
• jill
• kill

Kids Definition

ill

1 of 3 adjective

ˈil 

worse ˈwərs  ; worst ˈwərst 

1

: meant to do harm or evil

ill deeds

2

a

: causing suffering or distress

ill weather

b

: not normal or sound

ill health

c

: not being in good health

had been ill for some years

d

: affected by nausea

3

: not helpful to one : unlucky

an ill omen

4

: not right or proper

ill manners

5

: not kind or friendly

ill feeling

never said an ill word

ill

2 of 3 adverb

worse; worst

1

a

: with displeasure or anger

the remark was ill received

b

: in a harsh manner

treated me ill

2

: in a way that deserves blame

an ill-spent youth

ill-gotten gains

3

: hardly sense 3, scarcely

can ill afford it

4

: in a faulty way : badly, poorly

ill-prepared to face the winter

ill

3 of 3 noun

1

: the opposite of good : evil

2

a

: sickness sense 2

childhood ills

b

: trouble entry 2 sense 1a

the ills of society

Medical Definition

ill

1 of 2 adjective

ˈil 

worse ˈwərs  also iller ˈil-ər  ; worst ˈwərst 

1

: affected with some ailment : not in good health

incurably ill with cancer

—Time

mentally ill

2

: affected with nausea often to the point of vomiting

thought she would be ill after the ride on the roller coaster

ill

2 of 2 noun

: ailment, sickness

chickenpox and other ills of childhood