Translation guide
Describes something spreading quickly and uncontrollably, often in a negative sense. Japanese uses different words depending on what is rampant: crime, disease, plants, rumors, etc.
犯罪が横行している。
Crime is rampant.
雑草が生い茂っている。
Weeds are rampant.
To say that something bad is happening a lot and is hard to control.
Literally 'go sideways', used for negative things like crime, fraud, or bad behavior spreading widely. Often used in news.
この地域では詐欺が横行している。
Fraud is rampant in this area.
Spreading like a vine, used for diseases, bad influences, or negative phenomena. Stronger nuance of pervasive spread.
感染症が蔓延している。
Infectious diseases are rampant.
Very formal/literary, meaning 'to be at its height of rampancy'. Used for epidemics or evil forces.
悪疫が猖獗を極めた。
A plague was rampant.
To describe vegetation that has grown very densely and wildly.
For plants growing thickly and luxuriantly, often in an uncontrolled way.
庭に雑草が生い茂っている。
Weeds are rampant in the garden.
More formal term for lush, rampant growth of plants.
熱帯雨林では植物が繁茂している。
Plants are rampant in the tropical rainforest.
To say that rumors or gossip are spreading everywhere.
Rumors are flying around, rampant gossip.
会社ではリストラの噂が飛び交っている。
Rumors of layoffs are rampant in the company.
Speculation is rampant, often in media or public discourse.
事件の真相について様々な憶測が飛び交った。
Various speculations about the truth of the incident were rampant.
To describe wild, unchecked behavior or feelings.
Literally 'let loose', used for uncontrolled, rampant behavior or situations.
野放しの開発が環境を破壊している。
Rampant development is destroying the environment.
Idiom meaning 'unstoppable', used for rampant inflation, violence, etc.
インフレに歯止めが利かない。
Inflation is rampant.
English 'rampant' covers many situations, but Japanese requires different words for plants, diseases, rumors, etc. Using 蔓延する for weeds sounds odd; use 生い茂る instead.