For physical hardness:
* 硬 (yìng) - This is the most common way to say "hard" for physical objects. For example, a hard rock would be 硬石头 (yìng shítou).
For difficulty:
* 难 (nán) - This means "difficult" and is used to describe tasks, problems, or situations. For example, a hard question would be 难的问题 (nán de wèntí).
* 辛苦 (xīn kǔ) - This means "hard work" or "laborious" and is often used to describe tasks that require a lot of effort. For example, a hard job would be 辛苦的工作 (xīn kǔ de gōngzuò).
* 坚强 (jiānqiáng) - This means "strong" or "tough" and can be used to describe a person's willpower or resilience. For example, someone who is hard-working could be described as 坚强的人 (jiānqiáng de rén).
Other contexts:
* 硬 (yìng) can also be used to describe something that is inflexible or stubborn, like a hard heart (硬心肠 yìng xīncháng).
* 硬 (yìng) can also mean "firm" or "solid", such as a hard decision (硬性决定 yìngxìng juédìng).
Therefore, the best way to say "hard" in Chinese depends on the specific context. It's always helpful to consider the nuance and provide additional context to ensure clear communication.