You were hired because you are smart (researcher) or funny (comedian) or clever (analyst). You were hired because of your insights (strategist) or storytelling (marketer) or interpersonal skills (sales).
And you feel good about yourself. And you begin to move among and learn about others in your field. And you quickly realize that there is someone (perhaps many “someones”) who are smarter, funnier, more clever, insightful, who tells a better story or who connects more easily with more people.
Does this mean you are an impostor?
No.
It means that you are hanging out with exactly the right people.
There’s always someone who has “more” or is more of whatever you most value. The sooner you accept that and choose to learn from those you admire, the sooner you can get back to doing what you were hired to do.