Unyielding means refusing to bend or give way. Under pressure, and not moving.
It works physically, so unyielding rock and an unyielding surface give nothing when you push. It works on people just as well, and an unyielding opponent will not compromise, which can be praise or complaint depending on which side you are on. It takes in when a subject is named. The verb yield means to give way, and it also means to produce, as in a crop yielding well, which is a quite separate sense.
1adjectiveunyieldingRefusing to bend, give way or compromise.
“She was unyielding on the question of price.”
From un- + yielding.
Etymology from Wiktionary, CC BY-SA