Unwelcome mail is a term used to describe emails or letters that are unwanted or unsolicited. The crossword solutions for the term UNWELCOME MAIL are BILL (4 letters) and DEARJOHNS (9 letters). BILL is an acronym for 'Bulk Initiated Electronic Linking' which is a method of sending large amounts of emails at once. DEARJOHNS is a term used to describe emails sent to multiple recipients with the same message, usually in an attempt to solicit business.