Read the sentence.

Neither one of them knew the answer to the difficult question.

Which word is the indefinite adjective?

difficult

them

neither

one

difficult

The indefinite adjective in the sentence is "difficult."

The indefinite adjective in the sentence "Neither one of them knew the answer to the difficult question" is "difficult."

To identify the indefinite adjective, we first need to understand what an adjective is. An adjective is a word that describes or modifies a noun or pronoun, providing more information about it.

In this sentence, "difficult" describes the noun "question" and provides more information about it. The adjective "difficult" tells us that the question is not easy to answer.

Now, let's examine the options:
- "difficult" is an adjective that describes the noun "question."
- "them" is a pronoun that refers to multiple people and is not functioning as an adjective in this sentence.
- "neither" is a pronoun that indicates not one nor the other and is not functioning as an adjective in this sentence.
- "one" is a pronoun that refers to an individual and is not functioning as an adjective in this sentence.

Therefore, the correct answer is "difficult."