獗 (jué): (in 猖獗) rampant; unbridled

Meanings

走私活动一度十分猖獗。

Zǒusī huódòng yídù shífēn chāngjué.

Smuggling activity was rampant for a while.

疫情猖獗，全城都在戒备。

Yìqíng chāngjué, quánchéng dōu zài jièbèi.

The epidemic ran rampant, and the whole town was on guard.

usage

獗 appears only in 猖獗 (rampant, running wild), used for things that spread or act unchecked: crime, disease, pests. It has no independent use.

radical

犭 fǎnquǎnpáng

beast; animal

The side beast radical 犭 (a left form of 犬, dog) evokes wild, untamed animal behaviour, which matches the "running wild" sense of 猖獗.

phonetic

厥 jué

to faint; his/its (here phonetic)

On the right 厥 supplies the sound jué exactly. It is purely the phonetic element here.

獗 jué