Sturdiest

adjective

1. Of firm build; stiff; stout; strong.

   "a sturdy oak tree"

2. Solid in structure or person.

   "It was a sturdy building, able to withstand strong winds and cold weather."

3. Foolishly obstinate or resolute; stubborn.
4. Resolute, in a good sense; or firm, unyielding quality.

   "a man of sturdy piety or patriotism"