na-adjective
high-handed; oppressive; domineering
Describes a person, attitude, or method that is coercive, overbearing, or forces compliance without consideration.
彼の高圧的な態度に、みんなが反発した。
Everyone pushed back against his high-handed attitude.
Please stop giving orders in such an oppressive tone.
横柄 means 'arrogant' or 'haughty', focusing on a superior attitude, whereas 高圧的 stresses coercive, oppressive behavior.
Compound of 高圧 (high pressure) + 的 (-like, -ish). The figurative sense of 'high-handed' derives from the image of applying high pressure to force compliance.