It's likely you're thinking of "pontificate", which means:
* To speak or express opinions in a dogmatic or assertive manner, especially on a subject about which one is not an expert.
For example: "He likes to pontificate about the economy, even though he doesn't understand it."
It's important to note that "pontificate" can have a slightly negative connotation, implying that the speaker is being overly confident or self-important.