overconfidence

uncountable usually

An excessive or unwarranted degree of confidence.

Japanese Meaning

過剰な自信 / 根拠のない自信 / 自信過剰

His overconfidence led him to ignore the warnings and take unnecessary risks.

彼の自信過剰が原因で、警告を無視して不必要なリスクを取ってしまった。

Sense（1）

An excessive or unwarranted degree of confidence.

overconfidences

（ plural ）