Verb
To recant or recall, as what has been said; to refract; to take back again; to make as if not said.
Source: Webster's dictionaryIt is good for us to keep some account of our prayers, that we may not unsay them in our practice. Matthew Henry
A man of worth never gets up to unsay what he said yesterday. Chinua Achebe
He that is in haste may contract much guilt in a little time. What we say or do unadvisedly when we are hot, we must unsay or undo again when we are cool, or do worse. Matthew Henry
He swallowed his words Source: Internet