per·sist·ent / pərˈsistənt/ • adj. 1. continuing firmly or obstinately in a course of action in spite of difficulty or opposition: one of the government's most persistent critics. ∎  characterized by a specified habitual behavior pattern, esp. a dishonest or undesirable one: they accused officials of persistent discrimination.2. continuing to exist or endure over a prolonged period: persistent rain will affect many areas. ∎  occurring repeatedly over a prolonged period: persistent reports of human rights abuses by the military. ∎  (of a chemical or radioactivity) remaining within the environment for a long time after its introduction: PCBs are persistent environmental contaminants.3. Bot. & Zool. (of a part of an animal or plant, such as a horn, leaf, etc.) remaining attached instead of falling off in the normal manner.DERIVATIVES: per·sist·ent·ly adv.

persistent Describing a pesticide or other pollutant that is not readily broken down and can persist for long periods, causing damage in the environment. For example, the herbicides Paraquat and DDT can persist in the soil for many years after their application.