Why definition

wī, hwī
Frequency:
The reason for which.

Do you know why he went? this is why he went.

conjunction
12
2
The reason, cause, motive, purpose, etc.

Never mind the why and wherefore.

noun
10
1
Used to express mild surprise, indignation, or impatience.
interjection
9
2
The cause or intention underlying a given action or situation.

Studying the whys of antisocial behavior.

noun
9
3
A difficult problem or question.
noun
15
11
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Because of which; on account of which.

He knows of no reason why you shouldn't go.

conjunction
4
2
Used to express surprise, impatience, indignation, etc.
interjection
2
1
Used as an expletive, to preface a remark.
interjection
1
1
Why is defined as for what purpose, cause or reason.

An example of why is when it is used to ask a question such as "Why are you drinking water?

adverb
0
0
  • Introducing a complete question.
    Why is the sky blue?.
    Why did you do that?.
  • Introducing a verb phrase (bare infinitive clause).
    Why spend money on something you already get for free?.
    Why not tell him how you feel?.
  • Introducing a noun or other phrase.
    Why him? Why not someone taller?.
adverb
0
0
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The reason that.

I don't know why he did that; tell me why the moon changes phase.

conjunction
0
0
The reason.

A good article will cover the who, the what, the when, the where, the why and the how.

noun
0
0
Exclamation of mild surprise.
interjection
0
0
(UK, dialect) A young heifer.

noun
0
0
For what reason, cause, or purpose? with what motive?

Why did he go? he told her why he went.

adverb
4
5
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For what purpose, reason, or cause; with what intention, justification, or motive.

Why is the door shut? Why do birds sing?

adverb
1
2
The reason, cause, or purpose for which.

I know why you left.

conjunction
0
2
(usage problem) On account of which; for which.
conjunction
0
2
why not
  • all right; it's acceptable
idiom
0
1

Other Word Forms

Noun

Singular:
why
Plural:
whies, whys

Idioms and Phrasal Verbs

Origin of why

  • Middle English from Old English hwȳ kwo- in Indo-European roots

    From American Heritage Dictionary of the English Language, 5th Edition

  • From Middle English, from Old English hwȳ, hwÄ« (“why", instrumental case of hwæt (“what"), literally “by what, for what"), from Proto-Germanic *hwÄ« (“by what, how"), from Proto-Indo-European *kÊ·ey, locative of *kʷís (“who"). Cognate with Middle High German wiu (“how, why"), Danish and Swedish hvi (“why"), Faroese and Icelandic hví (“why"), Latin cui (“to whom", dative case of quÄ« (“who, how, why")), Ancient Greek πει (pei, “where"). Compare Old English þȳ (“because, since, on that account, therefore, then", literally “by that, for that"). See thy.

    From Wiktionary