赤信号|あかしんごうakashingou[3]nakadaka (mid-high)

1. nounred light (traffic)
   赤信号あかしんごうで通とおりを渡わたるのは危険きけんだ。↗

   It's dangerous for you to cross the street when the light is red.
2. nounred light; signal to stop; sign of danger
   それは実業じつぎょう人にんにとって一ひとつの赤信号あかしんごうになる。↗

   It raises a red flag for businessmen.

• Synonym赤色信号WrittenA written, explanatory term for a red signal; rare in everyday use — in speech say 「赤信号」.
• Antonym青信号あおしんごうNeutralThe green light, the opposite of 「赤信号」; figuratively it signals permission to go ahead.

Use 「赤信号」 for a red traffic light or, figuratively, a sign of danger, as in 「赤信号で止まる」 and 「健康の赤信号」; its counterpart is 「青信号」, the green light. 「赤色信号」 is a rare written alternative.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 危険きけんを知しらせる、または停止ていしをうながす赤色あかいろの灯火とうか信号しんごう。
2. 心配しんぱいすべき事態じたいがあるしるし。