Well, some is chunky.

But disregarding the larger bits of peanut in your peanut butter, the creamy texture of it is due to the fact that peanuts are mostly made of peanut oil.

The peanut butter you get in the store is made of very finely ground peanuts, so your tongue cannot feel the individual particles. They are surrounded by peanut oil, which is a liquid. The fine peanut flour absorbs the oil, and the result is a thick paste.

Of course peanut butter does not resemble cream in either color or consistency. The producers of peanut butter call it creamy because that sounds better than pasty.

Peanut butter contains very little moisture. In your mouth, it takes a while to eat peanut butter because you have to moisten it before you can swallow.