Here are some English phrases that you could use depending on the context:
* Bald: This is the most direct translation, but can be considered blunt.
* Hairless: This is another direct translation, but it's not commonly used in everyday speech.
* Bald-headed: This is a more formal way to say "bald."
* Having a receding hairline: This phrase implies that someone is losing their hair, but doesn't necessarily mean they're completely bald.
* Being bald: This is a neutral way to describe someone who is bald.
* Having a shaved head: This phrase is used if someone has intentionally shaved their head.
* A little thin on top: This is a humorous way to say that someone is losing their hair.
Ultimately, the best way to translate "mottai" depends on the specific situation and the desired level of formality.