Tanning and burning the skin is called Hadaga Kuroi (肌が黒い) as well.
When someone is strongly suspected of a crime, we use “Kuro” to mean “he must be Kuro!” which means he must be a criminal.”
Umini ittakara hadaga kurokunatta!
“I went to the sea, so my skin is tanned.”
Ne、fukuga sukoshi kurokunatteruyo!
“Hey, your clothes are a little darker!”
“Oh no, when did it get dirty?”
Kurono fukuga ichiban sukidesu。
“I like black clothes.”
What does Haraguroi(腹黒い) mean in Japanese?
Meaning: A wicked guy, A black-hearted guy
The word Haraguroi is a commonly used expression when talking about romantic relationships. A wicked guy is called Haraguroi Hito (腹黒い人), and a wicked woman is called Haraguroi Onna (腹黒い女).
Haraguroi has a negative connotation, so I don’t recommend saying it directly, even if the girl is wicked!
Ano onnawa haraguroi kara kiwotsukero!
“That woman is wicked, so be careful!”