Tenacious is a related term of unwavering.
As adjectives the difference between tenacious and unwavering
is that tenacious
is clinging to an object or surface; adhesive while unwavering
is never doubted; always steady and on course.
clinging to an object or surface; adhesive
unwilling to yield or give up; dogged
holding together; cohesive
having a good memory; retentive
* See also
Never doubted; always steady and on course