Let's define terms, then contextualize terms. Most misunderstanding come from how we define our terms. So let's define them.
In U.S. politics, a partisan is a committed member of a political party or political coalitions. In multi-party systems, the term is used for politicians who strongly support their party's policies and are reluctant to compromise with their political opponents
So if we throw those definition together it would look something like:
In U.S. politics, a partisan is a committed member of a political party or political coalitions. In multi-party systems, the term is used for politicians who absolutely support their party's policies and are unwillling to compromise with their political opponents
Emphasis mine on replacing words.
So there's a couple examples. I'll ask that you forgive my examples if they seem biased towards one party. I don't intend to target anyone, they are just solid examples.
So the first example of this sort of thing is the Republican Party vowing to stop President Elect (at the time) Obama at all costs:
Here’s John Boehner, the likely speaker if Republicans take the House, offering his plans for Obama’s agenda: “We're going to do everything — and I mean everything we can do — to kill it, stop it, slow it down, whatever we can.”
A key feature of this sort of this position is zero compromise. That in the end, it's not about compromise or building solid policy for all citizens, but to literally obstruct an opponent at all costs.
Again we see this with Merrick B. Garland, Obama's pick:
Senate Majority Leader Mitch McConnell declared any appointment by the sitting president to be null and void. He said the next Supreme Court justice should be chosen by the next president — to be elected later that year.
Again, refusal to compromise.
These are just two examples, but they're excellent examples of hyper-partisanship.