Adjective
1. 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"2. (of memory) having greater than average range;
"a long memory especially for insults""a tenacious memory"3. sticking together;
"two coherent sheets""tenacious burrs"