clueless

Definitions

Having no knowledge, understanding, or ability regarding a particular subject or situation.

Completely unaware or uninformed.

Examples

He was completely clueless about the surprise party being planned for him.

I felt absolutely clueless when the professor started explaining the complex physics equation.

She walked into the meeting looking clueless because she hadn't read the agenda beforehand.

Synonyms

ignorant oblivious uninformed naive bewildered unaware confused

Antonyms

knowledgeable aware informed perceptive astute enlightened sharp