The term PART SUIT can be broken down into two crossword solutions, VEST and 4 letters. A VEST is a sleeveless garment that is worn over a shirt or blouse and is usually part of a suit. It is typically made of wool, cotton, or synthetic fabrics and is often worn as part of formal attire. The 4 letters refer to the four-piece suit, which consists of a jacket, trousers, waistcoat, and sometimes a tie. This type of suit is traditionally worn for formal occasions such as weddings, funerals, and other special events.