persistent >> /pərˈsɪst(ə)nt/
Definition: [adjective] Continuing firmly or obstinately in a course of action in spite of difficulty or opposition.
Example: one of the government's most persistent critics
Definition: [adjective] Continuing to exist or endure over a prolonged period.
Example: persistent rain will affect many areas
Definition: [adjective] (of a part of an animal or plant, such as a horn, leaf, etc.) remaining attached instead of falling off in the normal manner.
Example: Both groups had woody stems that were heavily armored with persistent leaf bases, much like modern cycads.