怖さ

1. Origins, structure, and basic meaning

• Structure: 怖さ(こわさ) is a noun derived from the i-adjective 怖い(こわい) by replacing its final い with さ.
• Basic usage: It treats a frightening quality or feeling of fear as a subject, as with the dark sea or fear of failure.

2. Common pitfalls and similar expressions

• The adjective 怖い and its noun form
  • 怖い states that something is frightening, whereas 怖さ names that fear or frightening quality. In 失敗の怖さよりも, the entire noun phrase is compared with regret.