Unbidden
(adjective)
Not requested or commanded; done or given voluntarily.
Origin:
From the word bid meaning "to request or command" and the prefix un- meaning "not".
Examples:
- He arrived unbidden and uninvited.
- The memories came unbidden to her mind.
- The tears came unbidden to his eyes.
- He offered his help unbidden.
- The thoughts came unbidden during the meditation.