This is the 8095th most frequent Japanese word.
容赦
"容赦" means "mercy" or "forgiveness."
Here, 容赦 (mercy) is associated with a lack of leniency or forgiveness when conducting an action, emphasizing relentless behavior.
彼は敵に対して容赦なく攻撃した。
He attacked the enemy with no mercy.
In this case, 容赦 refers to granting leniency or forgiveness towards someone's mistake or wrongdoing.
どうか私の過ちを容赦してください。
Please forgive my mistake.
Here, 容赦ない (relentless) describes an unyielding and harsh quality, applied metaphorically to describe weather conditions.