adjective
unbidden
un-BID-un/ʌnˈbɪdn/
Coming or happening without being invited, requested, or consciously summoned.
The cat arrives unbidden at the dinner table and reaches for food.

Etymology
Bidden is the participle of bid in the sense of asking, inviting, or commanding. With negative un-, it describes someone or something arriving or happening without such a request or summons.
In context
Those significant incidents kept bobbing up in her mind like unbidden ghosts, without any sequence of time or place.
More examples
- He resents the unbidden advice about his parenting.
- She blinks away the unbidden tears that fill her eyes.
- An unbidden guest appears at their door during dinner.
Forms
unbidden
Similar words
- uninvited
- Usually describes someone arriving without an invitation, rather than thoughts.
- unsolicited
- Usually describes advice or offers given without a request.
- spontaneous
- Emphasizes a lack of planning rather than a missing request.