Worse.

See also: “Pretty close”

Good>pretty good

The word good is a stronger affirmative imo

Good

Pretty good

Really/Very good

Extremely good

Great

Pretty great

Really/very great

Extremely great

Awesome

…

I see “pretty good” to be better than just “good”. It seems obvious to me, considering one is only good but the other is pretty good.

I can’t imagine how “pretty good” could mean “better than good.” Most of the examples posted here are talking about how something relates to your expectations, but that’s not the question. Yes, “pretty good” is often used to describe something that is better than expected, but that doesn’t make it better than “good.”

For example, it doesn’t make sense to say “$50 is good, but $100 is pretty good!”

I do think “pretty good” is often used as an understated way to say that something is very good, e.g. “Yeah, Messi is pretty good at soccer.” However, that’s a play on the actual meaning of the phrase, and should not be construed as the actual meaning.