This is some unnecessarily fancy terminology for that time when God sacrificed his son for a weekend to act as a loophole around rules that he cobbled together four thousand years before (without explaining either the rationale for the rules in the first place or the loophole).
“Jesus died for your sins!”
If I owe you money, a third party can pay the debt and we’re done. This is what the Christians are asking you to accept as the metaphor of penal substitutionary atonement.
However, if I kick you in the balls and a third party pays the penalty (in this case, an apology), that means nothing. Your balls have still been kicked and I haven’t been affected at all. This far more suitable metaphor for penal substitutionary atonement illustrates how stupid it is.
All the big words in the world can’t change that.