I also sometimes invent words. Occasionally they've been previously used, as you say, perhaps with somewhat different meanings. I don't do it so much now.
I was addressing an important historical figure about whom there was tremendous controversy, even among his supporters. Having been a leading champion of justice for American Indians, he was accused of "selling out" after playing a supporting role in some Hollywood films. I supported his claim that acting was an extension of his activism, but not in the way he intended it. The words activist and activism helped me hone in on the kind of activist he had been from the beginning.
Russell Means?
Someone who likes crappy television should watch Survivor to see if they can draw the line between made-up sports and made-up games (not sports) among their "challenges".