向（む）き is another 名詞（めいし） (noun) in Japanese that is frequently used as a 接尾語（せつびご） (suffix).
向（む）き comes from the intransitive verb 向（む）く, meaning ‘to face’. This word is often attached to the end of other nouns, in order to show that something is ‘facing (A)’, or ‘suitable for (A)’.
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あなたは本当（ほんとう）に前（まえ） 向（む）きな人（ひと）なのですね。
You really are a forward facing person! (You really are a positive thinker)
この部屋（へや）は何（なに） 向（む）きですか？
Which way does this room face?
この本（ほん）は初心者（しょしんしゃ）向（む）きですか？
Is this book suitable for beginners?
Due to
向（む）き being intransitive, it usually implies that something is facing toward (A) naturally, or through chance. Because of this, it may convey that something is ‘suitable for (A)’, but not necessarily designed specifically for it.
向（む）け, coming from the transitive verb 向（む）ける is used far more often to express that something has been specifically designed for (A).
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私（わたし）は子供（こども）向（む）けの本（ほん）を書（か）いています。
I write books for children. (Intended for children)
子供（こども）向（む）きのほんをさがしているのですが、お勧（すす）めはありますか？
I am looking for books suitable for children, but do you have any recommendations? (Not necessarily intended for children, but still suitable)
When comparing
向（む）き and 向（む）け, the primary difference is that
向（む）き conveys that something is ‘appropriate for (A)’, while 向（む）け is closer to ‘intended for (A)’.