KanjiJLPT N1
Excessive

excessive, overflow, spread out

Mnemonic

A storm pounds the valley while the warden tries to oversee the reservoir. But the rainfall is so excessive that water overflows every boundary—no one can oversee such chaos. The flood spills indiscriminately, destroying everything in its path.
Additional thoughts
Picture a massive storm dumping so much rain that the official overseeing the dam is helpless—water pours over the banks in every direction, an image of unrestrained, indiscriminate excess beyond all limits.
Quick recall
A storm overwhelms anyone trying to oversee the flood—the deluge is excessive beyond all control.

Details

The keyword for 濫 is excessive. This kanji conveys the idea of overflowing beyond proper limits, suggesting something that has gone far beyond what is appropriate or necessary. It carries connotations of indiscriminate use, abuse, or unrestrained excess, as when resources are squandered or actions are taken without proper care or moderation. The sense of water spilling over its banks captures the core meaning of going beyond acceptable boundaries.
On'yomi
らん
Kun'yomi
みだ.りに、みだ.りがましい

Used in vocab