unyielding
adjective
[ ʌnˈjiːldɪŋ ]
• (of a mass or structure) not giving way to pressure; hard or solid.
• "the Atlantic hurled its waves at the unyielding rocks"
Similar:
stiff,
inflexible,
unpliable,
non-flexible,
unbending,
inelastic,
firm,
hard,
solid,
tough,
tight,
taut,
compact,
compacted,
compressed,
dense,
impliable,
unmalleable,
renitent,
