adj. 25B6; adjective
a very persistent man : TENACIOUS, persevering, determined, resolute, purposeful, dogged, single-minded, tireless, indefatigable, patient, unflagging, untiring, insistent, importunate, relentless, unrelenting; stubborn, intransigent, obstinate, obdurate; formal pertinacious.
persistent rain : CONSTANT, continuous, continuing, continual, non-stop, never-ending, steady, uninterrupted, unbroken, interminable, incessant, unceasing, endless, unending, perpetual, unremitting, unrelenting, relentless, unrelieved, sustained.
a persistent cough : CHRONIC, permanent, nagging, frequent; repeated, habitual.
irresolute, intermittent.