persistent
UK: pəˈsɪstənt | US: pərˈsɪstənt
adj. continuing firmly or obstinately in an action despite difficulty or opposition
adj. (of a phenomenon) enduring or recurring continuously
Derived from Latin persistere (to continue steadfastly), combining per- (through) and sistere (to stand). The root sist (as in "insist" or "resist") implies standing firm. Over time, persistent evolved to describe unwavering continuation, whether in behavior (e.g., effort) or natural phenomena (e.g., rain). The suffix -ent forms adjectives indicating a state or quality.
Her persistent efforts led to a breakthrough in the research.
The persistent rain flooded the streets for days.
He was persistent in asking for a raise until his boss agreed.
A persistent cough may indicate a serious health issue.
Despite setbacks, their persistent optimism kept the team motivated.