Expressing Suitable or Fit With 合适 or 适合

适合 shìhé and 合适 héshì they mean more or less the same thing, but the former is a verb, while the latter is an adjective.

适合 shìhé is a verb meaning "to suit," and should take an object.

Subj. + 适合shìhé + Obj.

Zhège gōngzuò bù shìhé nǐ, nǐ kuài cízhí ba!

这个工作不适合你，你快辞职吧！

This job is not suitable for you, so quit your job!

Zhè shì yī běn shìhé xiǎo háizi kàn de shū.

这是一本适合小孩子看的书。

This is a book suitable for children to read.

Zhè shuāng xié hěn shìhé nǐ. 

这双鞋很适合你。

This shoes suit you very well.

Wǒ juéde yīn tiān zuì shìhé páshān.

我觉得阴天最适合爬山。

I think cloudy days are most suitable for mountain climbing.

• Note : You can add intensifier in front of the 适合shìhé. e.g. hěn, fēicháng, zuì. 

合适héshì is an adjective meaning "suitable" or "appropriate," and is used in the same way as other adjectives.

Subj. + intensifier + 合适héshì

Gēn nà jiàn bǐ, zhè jiàn wàitào gèng héshì.

跟那件比，这件外套更合适。

Compared to that one, this coat is more suitable.

Yībiān shàngbān yībiān hējiǔ yǒudiǎn bù héshì ba!

一边上班一边喝酒有点不合适吧！

It's a bit inappropriate to work while drinking alcohol!

Zhǎodào yīgè héshì de gōngzuò bù róngyì.

找到一个合适的工作不容易。

It's not easy to find a suitable job.

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Let's look at a few more examples of them side by side to help clear out the differences：

     Zhè shuāng xiézi de yánsè héshì wǒ.

❎ 这双鞋子的颜色合适我。->合适héshì is not a verb.

   
    Zhè shuāng xiézi de yánsè shìhé wǒ.

✅  这双鞋子的颜色适合我。 -> Subj. + 适合shìhé + Obj.

      The color of these shoes is suitable for me.

      Zàijiā shàngbān duì tā zuì héshì. 

✅  在家上班对他最合适。-> Subj. + intensifier + 合适héshì

      Working from home is most suitable for him.

     Zàijiā shàngbān duì tā zuì shìhé.

❎ 在家上班对他最适合。->适合shìhé is a verb and should be followed by an object.