The phrase 'no matter who' indicates that something is applicable to all people, regardless of individual characteristics. Synonyms for this phrase include 'regardless of who', 'irrespective of who', 'whomever', 'whoever', 'anyone', 'everyone', 'each and every one' and 'all and sundry'. These words can be useful when writing formal letters, articles, or academic papers, where precision and accuracy are essential. It's crucial to choose the right synonym for the context and tone of the text. By using appropriate synonyms for 'no matter who,' writers can effectively convey that the information applies equally to all individuals, regardless of their background or social status.