What’s the difference between 符合, 适合 and 适应?

Question

They are all vocabulary from HSK 4. They are all verbs, and they are translated as “adapt”, “fit”, “suit”. Is there any difference in use or meaning between them? Thank you so much!

Answer 1

符合 means "match". Example:

他 符合 我们的 要求。

He matches our requirement.

适合 means “fit” in a sense of "good fit". Example:

他 很 适合 这个 职位。

He is a good fit.

符合 and 适合 have similar meanings but are often paired with different nones. I would say 符合 is a more precise fit than 适合。

适应 mean something quite different. It means "get used to", it is the process of getting to 符合 and 适合.

Answer 2

1. 符合

符合 is a transitive verb and means "to meet (a requirement)"， “to comply with". It's used mostly when talking about the accordance of something with some rule, form or standard.

出口产品必须符合相关法律法规 export products must comply with the relevant rules and regulations

你的思维不太符合逻辑 your line of thought isn't very logical (compliant with logic)

2. 适合

适合 is a transitive verb and means "to suit (someone/something)", or "to be suitable"; as opposed to 合适 which is always an adjective. It can also be used as "appropriate" (still transitive).

这很适合我的口味 this really suits my taste

适合野生动物栖息的地方 places that are suitable for wild animals (to dwell in)

跟朋友一起吃饭的时候不适合讨论政治问题 it's not appropriate to discuss politics when having dinner with friends

3. 适应

适应 can be used intransitively and transitively, and means "to adapt". Translating as "to fit/suit" is acceptable depending on the context, but the core meaning of the term is to adapt/adjust to something.

香港的气候我不适应 I can't adapt to the climate of Hong Kong

你可以更改这些字段的大小，以适应你的内容 you can change the size of these fields to fit (accommodate) your content

Answer 3

The book HSK汉语水平考试精选词汇辨析与练习 describes differences between closely related HSK words. Item 120 (page 119) addresses 符合, 合适, 适合, and 适应:

120. 符合 合适 适合 适应

120.1 词义解释
【符合】fú hé [accord with; tally with; conform to; coincide]
动（数量、形状、情节等）相一致。►这些产品的质量符合要求。

【合适】hé shì [fit; suitable; appropriate]
形 符合实际情况或客观要求。►我穿这件衣服大小很适合。

【适合】shì hé [agree with; suit; fit]
动 符合（客观实际）：合宜。►这部动画片很适合孩子们看。

【适应】shì yìng [adapt; accommodate]
动 随着条件的变化不断作相应的改变，使之适合。
►我们的产品只有适应市场的需要才有前途。

120.2 异同点辨析
“合适”，“适合”都指实际情况与客观要求一样，没有矛盾；能受程度副词修饰。不同的是，“合适”是形容词，在句子中常作谓语，也作定语、补语等，不能作状语；“适合”是动词，作谓语时可带宾语，可以作状语；不能重叠；常用于书面语。“符合”强调一个事物能与另一个事物在某些方面，例如数量、形状上完全一致，没有出入。“适应”强调为了适合客观的情况而做出相应的改变或调整；在句子中多作谓语，可带宾语；可以重叠为“适应适应”。

This last part explains their differences, which I translate to:

Both 合适 and 适合 indicate that actual situation is the same as the objective requirements, without contradiction; they can be modified by a degree adverb. The differences are that 合适 is an adjective, and is often used as a predicate [谓语], and also attribute (modifier) [定语], complement [补语], etc, cannot be used as an adverbial [状语]. 适合 is a verb. When used as a predicate [谓语] it can take an object [宾语] and can be used as an adverbial [状语]; it cannot reduplicate [重叠]; it is often used in written language. 符合 emphasizes that one thing is consistent with another, in some way such as quantity, shape, without discrepancy. 适应 emphasizes making appropriate changes or adjustments to suit objective conditions; in sentences it is more often a predicate [谓语], it can take an object [宾语]; can reduplicate [重叠] such as 适应适应.

I feel the biggest difference is that 合适 does not take an object, whereas 适合 can.

No object: 要是它不合适，你总还可以把它退回去嘛。 (YouDao)
If it doesn't suit, you always can return it.

Object: 这个太贵，而且颜色也不适合你。 (YouDao)
It's too expensive, and the color doesn't suit you.

My experience is that 符合 is typically used in formal settings (where there's some pre-defined specifications, like job applications), e.g.:

该灯设计得符合新的安全标准。 (YouDao)
The light is designed in accordance with the new safety standards.

As the book above highlights, 适应 highlights a change to make something suitable.

我需要适应新的时间表。 (YouDao)
I need to adapt to the new timetable.

I suggest taking a look at the above book which contains many examples, and even exercises.