Charles Ellicott Commentary Psalms 75:5

"Lift not up your horn on high; Speak not with a stiff neck." — Psalms 75:5 (ASV)

Lift not up your horn. —The “horn” is a symbol of honour (Psalms 112:9); of strength (Micah 4:13; Deuteronomy 33:17). The figure is taken from horned animals. (See 1 Samuel 2:1; 1 Samuel 2:10.)

With a stiff neck. —Better, with the neck proudly or wantonly raised.