And don't forget arrogance.
Arrogance and a superiority complex...........both absolutely vital!
Jargon and big words are for clever people who like to make themselves feel even cleverer by describing simple concepts in impressive ways to confound less clever people.
I suspect you don't bake too many cakes, so let's use beer as an example;
Directly proportional would describe the fact that when you drink more beer you become more pissed - (one up, the other up).
If you are a big lad, then you will be able to consume more beer than your little buddy, who will get pissed faster. So if you both drink 10 pints before climbing into your aircraft, he will have drunk proportionally more than you as he is so much smaller, and 10 pints occupies a much greater amount of his body.
Indirectly proportional would describe your ability to commit rumpy pumpy with the trolley dollies - more beer, less performance (one up, one down).
Easy really, and no stupid 'I'm a smart arse maths teacher' twaddle from a text book.