This is the 2103rd most frequent Japanese word.
失敗
"Failure" or "mistake."
The word '失敗' here is used as a noun indicating that someone did not succeed in an activity, specifically an exam.
彼は試験に失敗しました。
He failed the exam.
Here, '失敗' is used as a concept referring to the fact of failing, presented in a proverb to express encouragement.
失敗は成功のもとです。
Failure is the foundation of success.
In this sentence, '失敗' expresses a mishap or unsuccessful attempt in doing something, her cooking.