勿 – means “do not” or “don't” and is similar to 不要.
The 请勿[qǐnɡwù] structure:
勿 is often used together with 请 to form a fixed structure: 请勿 + verb / verb phrase. This fixed structure is used to courteously inform or advise others to refrain from doing a certain action (i.e. the action indicated by the verb / verb phrase in the fixed structure). In daily life, we often see this fixed structure used on signs.
The examples of 请勿[qǐnɡwù] structure:
请勿 + verb / verb phrase (请勿 as the adverbial in the sentences):
Wēnxīn tíshì: Wèile nínde jiànkānɡ, qǐnɡwù xīyān!
Friendly reminder: For your health, please do not smoke!
Gōngzuò shíjiān, qǐngwù dǎrǎo!
At work - please do not disturb!
Huìyì zhōnɡ, qǐnɡwù dǎrǎo!
Meeting in progress - please do not disturb!
Fēi gōngzuò rényuán, qǐngwù rùnèi!
Staff only! (Note: This is how it is commonly expressed in China. In Western countries, you might see a sign saying "No admittance - employees only"）
Wēnxīn tíshì: Qǐnɡwù dài chǒnɡwù rùnèi!
Friendly reminder: No pets allowed!
Huānyínɡ cānɡuān, qǐnɡwù pāizhào!
We welcome your visit, but please do not take any photos!
Wēnxīn tíshì: Qǐnɡwù suídì tǔtán, qǐnɡwù luànrēnɡ lājī!
Friendly reminder: No littering or spitting please!
Gōnɡzuò shíjiān, qǐnɡwù dàshēnɡ xuānhuá!
Please keep quiet during working hours!
Danger, please do not touch!
1. The difference between 勿 and 不要:
Both 勿 and 不要 mean “do not”. However, 勿 imparts a greater emphasis on refraining from the action referred to, has a slightly more serious tone and it is commonly used in written Chinese. On the other hand, 不要 does not have such a strong emphasis, has a more relaxed tone and is commonly used in daily oral conversation.
2. The difference between 勿 and 禁止:
禁止 is an HSK 4 level word and it means “to prohibit, forbid or ban”. Therefore, like 勿, its meaning can also loosely be interpreted as “don’t”. However, 勿 is more like a strong request or cautionary advice while 禁止 can be regarded as a type of order (i.e. as in ordering someone to refrain from doing something). In addition, 禁止 often refers an order that is based on a legal requirement or strict formal policy. It implies that this is a strict requirement that generally everyone must comply with.