unyielding

[ uhn-yeel-ding ]

/ ʌnˈyil dɪŋ /

unable to bend or be penetrated under pressure; hard: trees so unyielding that they broke in the harsh north winds.

not apt to give way under pressure; inflexible; firm: her unyielding faith.

Origin of unyielding

un-¹ + yielding

un·yield·ing·ly, adverb un·yield·ing·ness, noun

Spader, so intense and riveting last year as Red, has lost some of that unyielding relentlessness.

The Blacklist’s Frustrating Fall: Keen’s a Keeper, but Red Regresses |Jason Lynch |November 11, 2014 |DAILY BEAST
Both insisted Goldwater was scaring away the swing voters Republicans needed with his unyielding conservatism.

Barry Goldwater, Father of the Tea Party |Nicolaus Mills |July 16, 2014 |DAILY BEAST
[Hoffman] was definitely ferocious and unyielding in that movie.

My Lunch with Marisa Tomei: The Actress on ‘The Realistic Joneses,’ ‘Girls,’ and de Blasio’s NYC |Marlow Stern |April 23, 2014 |DAILY BEAST
That standard and his unyielding hold to keeping up those standards made me want to work harder, but I only realized that after.

My Lunch with Marisa Tomei: The Actress on ‘The Realistic Joneses,’ ‘Girls,’ and de Blasio’s NYC |Marlow Stern |April 23, 2014 |DAILY BEAST

She wore an apple-green housedress and her graying beehive hairdo was unyielding against the blasts of a chugging air conditioner.

What Lee Harvey Oswald’s Mother Told Me |Lloyd Grove |November 14, 2013 |DAILY BEAST
The king grew angry, but the duke remained firm and unyielding.

Sweden |Victor Nilsson
So tangled and unyielding was the mass that even dynamite had little effect upon it.

The Complete Story of the Galveston Horror |Various
For a moment their glances met, the woman's hot and angry, the man's cold and unyielding.

The Golden Amazons of Venus |John Murray Reynolds
The masses of roots are as unyielding as iron, and run twisting through the soil to the distance of sixty yards.

Among the Trees at Elmridge |Ella Rodman Church
His victim had now become his tyrant; not implacable or vindictive, but firm and unyielding in the discharge of his duty.

Brave Old Salt |Oliver Optic

unyielding

/ (ʌnˈjiːldɪŋ) /

not compliant, submissive, or flexible his unyielding attitude

not pliable or soft a firm and unyielding surface