Mammoth Uncensored Word List:
20 words ending with ar, 15 letters long

cerebrovascular extracurricular extrafollicular extraglomerular interclavicular interfascicular intertentacular intracerebellar intrafascicular intraglomerular juxtaglomerular musculocellular periventricular pharyngobasilar pontocerebellar skeletomuscular spinocerebellar stylomandibular subquadrangular supraclavicular