Holy Mackerel is an exclamation of surprise or amazement. It is often used to express shock or disbelief. The crossword solutions for the term 'Holy Mackerel' include Yowee (5 letters), WOW (3 letters), MAN (3 letters), Egad (4 letters), Zowie (5 letters), GEE (3 letters), Yikes (5 letters), Jeez (4 letters), Yipes (5 letters), GreatScott (10 letters), and JiminyChristmas (15 letters). All of these words are expressions of surprise or amazement, and they are often used in place of the phrase 'Holy Mackerel'.