It's possible you are thinking of a related concept, like:
* Imperative verbs: These are verbs used to give commands or instructions. They are typically in the second person ("you"). Example: "Close the door!"
* Imperfect verbs: This is a grammatical tense in some languages, like Spanish or French, that describes an action happening in the past but not necessarily completed. It's not a concept commonly used in English.
* Formal or official language: Some might use "imperial" as a metaphorical description of a verb used in a very formal or official setting, like a legal document or government decree.
If you can provide more context about where you encountered the term "imperial verb," I might be able to help you understand its meaning.