tenacious
1. [ adjective ] (of memory) having greater than average range
Synonyms: long
Examples:

"a long memory especially for insults" "a tenacious memory"

Related terms: retentive
2. [ adjective ] stubbornly unyielding
Synonyms: dogged pertinacious dour unyielding bulldog
Examples:

"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"

Related terms: stubborn
3. [ adjective ] sticking together
Synonyms: coherent
Examples:

"two coherent sheets" "tenacious burrs"

Related terms: adhesive
Similar spelling:   tenaciously