Billy Butcher and the Boys held down a 10 year old boy and cut off his tongue. This was to prevent him from uttering his magical word, which turns him into super-powered individual 5 times his current size. The Boys targeted this kid because whenever he becomes his alter-ego, he had the habit of raping other people.
From what I can tell on the word the kid was trying to yell, it seems like Shazam. lol
From – The Boys: Dear Becky #1