Those two words and their relationship with "consent" and "freedom" fascinate me. I've sort of ruminated about it in the back of my mind for a while, but haven't sorted a lot out.
It would be nice for two people to be able to make any agreement they like between each other without restrictions. "I'll do this for me and you give me that in return". If there aren't restrictions on what sort of agreement two private people make, in some sense, that can be maximum freedom.
But then exploitation and coercion come into the mix. "If you don't sign this contract, I will kill you" is a clear example of an agreement not being free. "If you don't sign this employment contract, you won't be able to afford to buy food" is still fairly clear, but a little further removed. "If you don't sign this employment contract, you'll be able to get food, but the food you can afford will be heavily processed and laden with oils and processed sugars, and you could suffer poor health in the future" is getting into a lot of grey area.
We talk a lot about minimum wage workers being exploited. It's true that most of them (almost all of them?) hate their jobs. It's also true that life necessarily requires sacrifices. I don't have a good framework for thinking about what point something becomes exploitative or unethical.
It comes up in personal relationships as well. "If you don't have sex with me, I will kill myself" is clearly abusive and manipulative. "If you don't have sex with me, I will break up with you" is slightly more removed. "If you don't quit using heroin, I will break up with you" is a little grey.
At what point is someone being coerced in a relationship vs two people acknowledging sacrifices they have to make to stay together? I don't have a good framework for thinking about this.
Further things to think about: at what point of mental illness can a person no longer ethically enter into an agreement? What about a normal person who suffers from the usual human psychological biases? At what point is it exploitative to use psychological biases when negotiating with someone? This can go all the way from the benign (ending a price in ".99") to the damaging (designing casino games with flashing lights and buzzers, etc.)
I don't expect someone to be able to give me a pat answer to this. If you think you can give me a 1-line "Exploitation is ...", I think you're probably missing something. But I am curious how other people think about these things, and what examples or what books you've found that have been helpful to you sorting things out.