- Presumptuous describes someone who oversteps the limits of courtesy or politeness.
- Presumptive is a different word. It describes something that is expected to happen or become true.
When you say someone is presumptuous, you mean that the person is overconfident and is acting rudely or inappropriately. A presumptuous person takes liberties. Wandering into the kitchen at the home of an acquaintance and helping yourself to the contents of their refrigerator, for instance, would be presumptuous.
Definition of Presumptuous
It’s not nice to be presumptuous. In fact, when someone calls you that, they are saying that you’re acting out of line in a way that’s much more rude than awkward. They might also be saying that you’re overconfident, that you take too many liberties, or that you’re acting in a bold and unwarranted way. When you’re doing something you have no right to do, or something you’re not permitted to do, you can say that you’re presumptuous:
Synonyms for Presumptuous
What are the other ways you can say that someone is being presumptuous? Well, people who are presumptuous are commonly seen as rude or smug, so those two might be good synonyms. But you can also say they’re being too forward, pushy, or even pretentious. Arrogance and overconfidence go hand in hand with presumptuousness, so they too should be added to the list of synonyms.
Presumptive vs. Presumptuous
Presumptive and presumptuous sort of sound alike because they have the same root word, and they are both adjectives. But they don’t mean the same thing. You know by now that presumptuous means taking liberties. But if something is presumptive, it means that it is probable or expected:
In this sentence, presumptive is synonymous with “probable.” But if we changed presumptive to presumptuous, we wouldn’t characterize Marissa as the possible future CEO—we would say that she’s a future CEO who is rude and overconfident.
from Grammarly Blog https://www.grammarly.com/blog/presumptuous/