[ il ]
See synonyms for ill on
adjective,worse, worst;ill·er, ill·est for 7.
  1. of unsound physical or mental health;unwell; sick: She felt ill, so her teacher sent her to the nurse.

  1. hostile; unkindly: ill feeling.

  2. evil; wicked; bad: of ill repute.

  3. unfavorable; adverse: ill fortune.

  4. of inferior worth or ability; unskillful; inexpert: an ill example of scholarship.

  5. Slang. great; amazing: His mom is the illest cook.

  1. an unfavorable opinion or statement: I can speak no ill of her.

  2. harm or injury: His remarks did much ill.

  1. trouble, distress, or misfortune: Many ills befell him.

  2. evil: to know the difference between good and ill.

  3. sickness or disease.

  1. in an ill manner.

  2. unsatisfactorily; poorly: It ill befits a man to betray old friends.

  1. in a hostile or unfriendly manner.

  2. unfavorably; unfortunately.

  3. with displeasure or offense.

  4. faultily; improperly.

  5. with difficulty or inconvenience; scarcely: Buying a new car is an expense we can ill afford.

Idioms about ill

  1. ill at ease, socially uncomfortable; nervous: They were ill at ease because they didn't speak the language.

Origin of ill

1150–1200; Middle English ill(e) (noun and adj.) <Old Norse illr (adj.) ill, bad

synonym study For ill

1. Ill, sick mean being in bad health, not being well. Ill is the more formal word. In the U.S. the two words are used practically interchangeably except that sick is always used when the word modifies the following noun: He looks sick ( ill ); a sick person. In England, sick is not interchangeable with ill, but usually has the connotation of nauseous: She got sick and threw up. sick, however, is used before nouns just as in the U.S.: a sick man.

Grammar notes for ill

See well1.

Other words for ill

Opposites for ill

Words that may be confused with ill

  • ill , sick (see synonym study at the current entry)

Words Nearby ill

Other definitions for I'll (2 of 4)

[ ahyl ]

  1. contraction of I will.

usage note For I'll

Words that may be confused with I'll

Other definitions for ill. (3 of 4)


  1. illustrated.

  2. illustration.

  1. illustrator.

  2. most illustrious.

Origin of ill.

(def. 4) <Latin illustrissimus

Other definitions for Ill. (4 of 4)


  1. Illinois. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use ill in a sentence

British Dictionary definitions for ill (1 of 3)


/ (ɪl) /

adjectiveworse or worst
  1. (usually postpositive) not in good health; sick

  2. characterized by or intending evil, harm, etc; hostile: ill deeds

  1. causing or resulting in pain, harm, adversity, etc: ill effects

  2. ascribing or imputing evil to something referred to: ill repute

  3. promising an unfavourable outcome; unpropitious: an ill omen

  4. harsh; lacking kindness: ill will

  5. not up to an acceptable standard; faulty: ill manners

  6. ill at ease unable to relax; uncomfortable

  1. evil or harm: to wish a person ill

  2. a mild disease

  1. misfortune; trouble

  1. badly: the title ill befits him

  2. with difficulty; hardly: he can ill afford the money

  1. not rightly: she ill deserves such good fortune

Origin of ill

C11 (in the sense: evil): from Old Norse illr bad

British Dictionary definitions for I'll (2 of 3)


/ (aɪl) /

contraction of
  1. I will or I shall

British Dictionary definitions for Ill. (3 of 3)


abbreviation for
  1. Illinois

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Idioms and Phrases with ill


In addition to the idioms beginning with ill

  • ill at ease
  • ill wind that blows no one any good, it's an

, also see under

  • get sick

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.