Qualifiers are terms used to describe a certain set of criteria that must be met in order for something to be accepted. In the context of a crossword puzzle, the solutions HEATS (5 letters), IFS (3 letters), and BUTS (4 letters) all refer to qualifiers. HEATS stands for 'Head-to-head Elimination All-Star Tournament Series', which is a type of tournament where two players compete against each other in a series of rounds until one is eliminated. IFS stands for 'Informal Qualifying Standards', which are standards that are not formally established but are still used to determine eligibility for something. BUTS stands for 'Bona Fide Unrestricted Tournament Series', which is a type of tournament where players compete against each other without any restrictions.