Normally people say exponential, but I think that's a silly term as it is quite a specific term since it means that the exponent is a variable (e.g. 2^x, 3^x, for every n, so n^x). For example, x^2 is super linear, but it isn't exponential. Yet, I'm fairly sure that I've heard people say that something is "exploding exponentially" but what they meant is that it's super linear since they got the faintest clue how much faster their projections are going compared to a linear projection.
It's OK everyone. You don't have to endlessly add superlatives to your ideas to make them sound more exciting. Just say linear. It's SUPER effective!