what does iron fist mean?

IRON FIST as NOUN

Meaning
- rigorous or ruthless control
Usage Example(s)
- she rules the office with an iron fist
- it takes an iron fist to contain the dissenting factions
Hypernyms(s) iron fist is a kind of… Example: animal is a hypernym of mammal, plant is a hypernym of flower
- control (what does control mean?)