Dictionary entry

σκληροτράχηλος

G. Abbott-Smith's A Manual Greek Lexicon of the New Testament with Strong's

σκληρο-τράχηλος, -ον

(σκληρός, τράχηλος), [in LXX: Ex 33:3, 5 (עֹרֶף ־קָשֶׁה), etc.;]

stiff-necked: metaph., Ac 7:51.†