If you're looking for a word that sounds similar, perhaps you meant:
* "Pompous": This describes someone who is arrogant and self-important, often in a way that is exaggerated or pretentious.
* "Preposterous": This means absurd or ridiculous, often in a way that is unbelievable.
* "Picturesque": This describes something that is visually appealing and charming, often in a way that is reminiscent of paintings.
If you could provide some context about where you saw or heard the word "popestrous", it might be easier to understand what you're looking for.