To violate a religious or moral law.
To utter (something) stupidly or thoughtlessly.
(Brit., Slang) To make a stupid mistake
To waste or kill time:
Find another word for drop-the-ball. In this page you can discover 4 synonyms, antonyms, idiomatic expressions, and related words for drop-the-ball, like: sin, blunder, boob and goof.