iron grip

1. An extremely strong or unbreakable grip, as with one's hands. Man, he must lift weights or something, because he had an iron grip when he grabbed hold of my arm! You want to tighten the clamp until you get an iron grip. The last thing you want is the frame to wobble or move out of alignment. You want to tighten the clamp until you have an iron grip. The last thing you want is the frame to wobble or move out of alignment.

2. Total, dominant control (over someone or something). The dictator maintained an iron grip over the country and its people, quashing any uprising or dissent with extreme violence. The tech giant is finally facing pressure from the government for the iron grip it's had on the smartphone industry for the last decade. I never liked them together. To me, he always seemed way too controlling, like he wanted to have an iron grip on her.