boob vs drop the ball

boob is a noun but drop the ball is not a noun.

Word	Noun	Adjective	Verb	Adverb
boob	Yes	No	Yes	No
drop the ball	No	No	Yes	No

As verbs, boob and drop the ball are synonyms defined as:

boob and drop the ball: commit a faux pas or a fault or make a serious mistake

Other synonyms of boob include blunder, goof, sin.

boob (noun)	drop the ball (noun)
either of two soft fleshy milk-secreting glandular organs on the chest of a woman
an ignorant or foolish person

boob (verb)	drop the ball (verb)
commit a faux pas or a fault or make a serious mistake	commit a faux pas or a fault or make a serious mistake