"Expunction" Natural Recordings by Native Speakers
Expunction refers to the process of officially erasing or wiping out a past mistake or record, typically a criminal conviction or a debit from a person's credit report.
Expugn is a verb that means to capture or conquer a place or stronghold by force, especially in battle.
I'm afraid there is no word "expugner" in the English language. It's possible that it's a made-up or non-standard term. If you meant to say "expunger", an expunger is a person who clears or removes something, especially a writer who corrects or revises written work.
Expulsion refers to the act of forcing someone to leave a place, institution, or organization, often as a penalty or consequence of a wrongdoing. It can also refer to the act of expelling something, such as a foreign substance or a person, from a place or a part of a thing.
To expurgate something means to remove or to censor offensive, obscene, or sensitive content from it, often to make it more acceptable or suitable for a wider audience. This can refer to books, documents, speeches, or other written or spoken materials.