The term 'talk boastfully' can be summarized by two crossword solutions: 'VAUNT' (5 letters) and 'BRAG' (4 letters). VAUNT is a verb meaning to speak or act in an excessively proud and self-important way, while BRAG is a verb meaning to talk with excessive pride and self-satisfaction about one's achievements, possessions, or abilities. Both words are used to describe someone who talks in an overly boastful manner.