What part of speech is “why”

why is an adverb that is used to refer to an explanation or a cause, a purpose, or a motive. It is often used as an interrogative to ask for a person’s reasoning or purpose. For example, 'Why did you do that?' or 'Why did she leave?'

1. 'Why do they need more money?'

2. 'The why of this experiment is still unclear.'

3. 'Why is she even here?'

when using why as an adverb, it should be preceded by an article ('the', 'a', or 'an'), and it can be used with prepositions such as 'for' or 'of'. Common mistakes include omitting the article before 'why' or using why as an adverb (for example, saying 'Why quickly did he leave?').

'why' can be used to introduce a clause that explains the reason or cause for a particular statement or action. When used as a conjunction, 'why' can often be found in exclamatory sentences to express surprise, disagreement, or another emotion.

She's upset, why I don't know.

You're going to the party, why I can't understand.

He's always late, why remains a mystery.

when 'why' is used as a conjunction, it often gives the sentence a more informal or colloquial tone. In formal writing, it might be more appropriate to rephrase the sentence for clarity. Avoid confusing the conjunctive use of 'why' with its more common interrogative use. For instance, 'Why did he go?' is an interrogative use, while 'He went, why I don't know' uses 'why' as a conjunction.