無駄(むだ)

waste; useless

駄目(だめ)

no good; useless

下駄(げた)

traditional Japanese wooden sandals

駄菓子(だがし)

cheap snack; inexpensive sweets

駄作(ださく)

poor-quality work; inferior piece

駄賃(だちん)

fare; payment for carrying something

駄洒落(だじゃれ)

pun; bad joke

駄々(だだ)っ子(こ)

spoiled child; child who throws tantrums

そんなに悩(なや)むのは無駄(むだ)です。

It is pointless to worry so much.

駄菓子屋(だがしや)で飴(あめ)を買(か)いました。

I bought candy at a dagashi shop.