σκληροτράχηλος sklērotráchēlos

Meaning

hardnaped, i.e. (figuratively) obstinate

In the King James Version: stiffnecked

Derivation: from G4642 (σκληρός) and G5137 (τράχηλος);

Where it is used

• Acts 7:51 You stiff-necked people with uncircumcised hearts and ears! You always resist the Holy Spirit, just as your fathers did.