na-adjective, noun
exaggeration; making a mountain out of a molehill
A yojijukugo meaning to greatly exaggerate a small matter. Often used in the phrase 針小棒大に言う (to exaggerate).
彼の話はいつも針小棒大だ。
His stories are always exaggerated.
その噂は針小棒大に伝えられた。
The rumor was blown out of proportion.