retained; not shed; "persistent leaves remain attached past maturity"; "the persistent gills of fishes"保持する永続的
例:The persistent gills of fishes. 魚の永続的なエラ。
never-ceasing; "the relentless beat of the drums"決して終わらないさま持続的
stubbornly unyielding; "dogged persistence"; "dour determination"; "the most vocal and pertinacious of all the critics"; "a mind not gifted to discover truth but tenacious to hold it"- T.S.Eliot; "men tenacious of opinion"頑固なほど不屈な根暗