Depending on the specific usage, the opposite of "salutation" could be:
* Valediction: This refers to the closing words of a letter or speech, like "Sincerely" or "Yours truly."
* Farewell: This implies a goodbye or parting.
* Disrespect: This refers to a lack of polite or courteous behavior.
* Dismissal: This implies rejecting or ignoring someone.
* Insult: This is a rude or offensive remark.
Example:
* Salutation: "Dear Mr. Smith,"
* Valediction: "Sincerely, John Doe"
Therefore, the best opposite depends on how "salutation" is being used.