All these terms can be used not allowed/prohibited both mean something is not to happen or to be done
Please could be added to the no graffiti as its a nicer way of putting it
‘No graffiti’ is the most common sign that would be seen in the UK because it is a short and sharp message that is easy to fit in large letters onto signs. The phrase ‘graffiti is strictly prohibited’ is much more severe and implies that there will be punishment for anyone caught in the act. ‘Do not graffiti here’ is seen less often because it is not as severe and doesn’t suggest a punishment.
「No graffiti」は英国で見られる最も一般的な看板です。短く適確なメッセージで、大きな文字で看板におさめることができます。
「Graffiti is strictly prohibited」は「No graffiti」よりずっと厳しい言い方です。捕まった人に罰があるというニュアンスです。
「Do not graffiti here」はそれほど見かけません。あまり厳しい言い方ではなく、罰のニュアンスがありません。
Often signs in public areas where graffiti is not permitted to say the following:
No graffiti!
No graffiti allowed!
Graffiti is strictly prohibited!
When writing commands, remember to add an exclamation point '!' at the end of the sentence.
The word 'to prohibit' and it's adjectival form 'prohibited' mean 'to ban, to not allow' and 'banned, not allowed'.
公共の場所で見かける落書き禁止の看板には下記のように書かれていることが多いです：
No graffiti!（落書き禁止！）
No graffiti allowed!（落書き禁止！）
Graffiti is strictly prohibited!（落書き厳禁！）
何か命令する文を書く時には、文の最後に感嘆符「！」を付けてください。
'to prohibit'、およびその形容詞形の'prohibited'は、「禁止する」「禁止された」という意味です。
Graffiti' as defined is deliberately defacing public or private property by writing or drawing on the property. So it makes sense that people would not want this on the walls. However Graffiti has become an art and can be quite incredible. The most common way to prevent this from occuring is to either place a sign saying 'No Graffiti'... this may or may not work.
Another form of vandalism is to post signs or posters on public and private spaces. Hence the expression 'post no bills'.
Graffiti'（落書き）は、公共または個人の所有物を、文字や絵を描いて傷つけることを言います。人々が壁にこれをされたくない思うのは当然ですね。
しかし、芸術としての'Graffiti'もあって、これはすばらしいです。
落書きを防ぐ最も一般的な方法は、'No Graffiti'というサインを置くことです。防げるかどうかは分かりません、、、
もう一つの文化芸術の破壊行為としては、公共や私有のスペースにサインやポスターを掲示することがあります。この場合は、'post no bills'（張り紙お断り）という表現があります。
Using the word 'please' is a polite way of asking something. Instead of using an aggressive stance of 'no graffiti!!!' which is unlikely to stop people from graffitiing try using a more gentle and polite approach.
Some cities and towns have areas set aside so that graffiti artists can do there art there. However it is not always seen as an art especially when something has been vandalised.
The third example sentence above is a very soft way of stating that someone should not do something. In the UK, we often 'understate' things and such a soft reminder should not be taken as meaning that there are no severe consequences for offenders.
アメリカ合衆国 
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オーストラリア 
