Problem is that if the word "subsidies" is used exclusively to mean a specific and narrow concept around cash transfers when talking about renewables, but then

Problem is that if the word "subsidies" is used exclusively to mean a specific and narrow concept around cash transfers when talking about renewables, but then you use the term to include a much broader set of scenarios when talking about fossil fuels, while directly comparing the derived numbers, then you're misusing the language in order to deceive, regardless of all else. You're communicating that the numbers represent the same calculations for both forms of energy, when you know that they actually don't. Define the terms however you like, as long as you are careful to not to induce people to believe someone that is untrue.