Bad Habit, Bad Taste
noun, な adjective
Your 趣味 is your hobby. It's the thing you do on habit. A bad hobby is a habit that you do all the time that's no good. This is a bad habit.
あくしゅみ
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
母は、父が悪趣味な人形を集めることを禁止しました。
My mom forbade my dad from collecting tasteless dolls.