Unprompted (adjective)

Not induced or encouraged by a specific stimulus.

Origin:

The word "unprompted" is formed by the prefix "un-" which means not, and the word "prompted" which means induced or encouraged by a specific stimulus. together they form an adjective that means not induced or encouraged by a specific stimulus.

Examples:

1. He spoke unprompted, he didn't wait for a question to be asked.
2. She sang unprompted, she didn't wait for an invitation.
3. The dog barked unprompted, it wasn't responding to a command.
4. The child laughed unprompted, it wasn't prompted by a joke.
5. The horse neighed unprompted, it wasn't responding to a whistle.