The term 'Cousin of 'Kapow!' ' can be solved by two crossword solutions: BAM (3 letters) and WHAM (4 letters). BAM and WHAM are both onomatopoeic words used to describe a loud sound, usually associated with a physical impact. BAM is a shorter, sharper sound, while WHAM is a longer, more drawn out sound. Both words are often used in comic books and cartoons to indicate a physical impact, such as a punch or explosion.