Dangerous! Don’t do it! Careful!

Abunai!!  
Dangerous!! 

Abunai!!  Naka ni hairanaide kudasai.
Dangerous!! Please, do not go inside.

Abunai kara haitte wa ikemasen!  
Because it is dangerous, you are not allowed to go inside! 

Abunai! Haitte wa ikemasen!  
Dangerous! You are not allowed to go inside! 

Abunai!! Koko de asonde wa ikemasen!  
Dangerous!! Playing here is not allowed. 

Abunai! Haitte wa ikemasen!  
Dangerous! You are not allowed to go inside!

Abunai kara haitte wa ikemasen.  
Because it is dangerous, you are not allowed to enter. 

Abunai!! Koko de asonde wa ikemasen!  
Dangerous!! Playing here is not allowed.

Koko de asobu to abunai yo!  
If you play here, that will be dangerous!

Abunai!!  
Kiken desu node, hairanaide kudasai.
Dangerous!! 
As it is a danger, please don’t enter.

Abunai!!  
Kawa ni, hairanai yō  ni shiyō.

Dangerous!! 
Let’s not get into the river.

Abunai kara haitte wa ikemasen.  
Because it is dangerous, you are not allowed to enter. 

Abunai!! Koko de asonde wa ikemasen!  
Dangerous!! Playing here is not allowed.

Abunai!!  Kono naka ni haitte wa ikemasen.
Dangerous!! You are not allowed to go inside here.

Kiken! 
Danger!
Abunai kara sawatte wa ikemasen.  
Because it is dangerous, you are not allowed to touch this. 

Abunai kara haitte wa ikemasen.  
Because it is dangerous, you are not allowed to enter. 

Abunai!! Koko de asonde wa ikemasen!  
Dangerous!! Playing here is not allowed.

Abunai!! Koko de asonde wa ikemasen!  
Dangerous!! Playing here is not allowed.

Inu o irete wa ikemasen
It’s forbidden to put your dog in there.

Kono naka e haitte wa ikemasen.
You are not allowed to go inside here.

Haitte wa ikemasen.
You are not allowed to enter.

Dangerous あぶない

Dangerous!

Entry not allowed

If you are in Japan, or even in China, good kanji to recognise:

kiken   きけん　danger; peril; hazard