The contraction mightn't is a combination of the auxiliary verb 'might' and the adverb'not'.

Example: We might not have time to finish. OR: We mightn't have time to finish.

The word mightn't is a contraction, a shortened form of the auxiliary verb 'might' and the adverb 'not'.

'Might not' is most commonly used to express negative possibility:

• She might not have taken the bus.
  
• She mightn't have taken the bus.

A pronoun is a word that takes the place of a noun in a sentence. The pronoun 'she' takes the place of a noun (name) for a female as the subject of the example sentence above.

A noun is a word for a person, a place, or a thing. The noun in the example sentence is 'bus', a word for a thing.

The word mightn't is a contraction, a shortened form of the auxiliary verb 'might' and the adverb'not'.

'Might not' is most commonly used to express negative possibility:

• She might not have taken the bus.
  
• She mightn't have taken the bus.