Boggle (verb)

1. To be startled or confused by something unexpected or difficult to understand.
2. To hesitate or be uncertain about how to react or respond.

Origin:

The word boggle is thought to have originated in the 16th century, it is likely an onomatopoeic word, which refers to the action of being startled or confused by something unexpected or difficult to understand.

Examples:

1. The news boggled my mind.
2. He boggled at the difficult math problem.
3. The complexity of the project boggled her.
4. The proposal boggled the board members.
5. The idea of traveling to space boggled his imagination.