tenacious

adjective4

1. •
   Clinging to an object or surface; adhesive.
2. •
   Unwilling to yield or give up; dogged.
3. •
   Holding together; cohesive.

   • The quagmiry road, trodden into tenacious paste by the long file of human beings ahead […] — 1873
4. •
   Having a good memory; retentive.