Two of DC and Marvel's most powerful titans of thunder are Black Adam and Thor. Both lightning-wielding characters remain some of the strongest comic book figures of all time. In terms of their personalities, they are also not so different. Both Thor Odinson and Teth Adam are considered royalty in each of their homes. Furthermore, they both have more than 1,000 years of life under their belts. With that said, who would win if one challenged the other?
Most heroes of the DC Universe fear "the man in black himself, Black Adam," as Dwayne "the Rock" Johnson (soon to be Black Adam in the DCEU) calls him. In the comics, Teth Adam lives in Kahndaq, a country similar to Ancient Egypt. The Wizard Shazam chooses Teth as his champion, like how he chooses Billy Batson to be DC's Captain Marvel (Shazam). Teth becomes Black Adam, using his powers for selfish and evil reasons. Because of this, the Wizard Shazam banishes him to the furthest reaches of space. He eventually returns to Kahndaq, in modern comics, and takes over as its new dictator. Adam has the same powers as Captain Marvel—flight, super-strength, super-speed, powerful lightning attacks, and additional magical abilities—but his actions are far more ruthless. He usually makes examples of his enemies by dismembering them or frying them with his lightning powers.
Thanks to the Marvel Cinematic Universe, most people know who Thor Odinson is. In Marvel Comics, Thor has similar origins to the MCU—he learns humility on Midgard (Earth) and decides to defend the universe as an Avenger. Thor frequently battles some of Marvel's most destructive villains, such as Galactus and Thanos. Thor also has a pure heart, allowing him to wield his hammer, Mjolnir. He has complete control over the Uru hammer as it helps him smash his foes, fly, and summon lightning. It's uncommon for Thor to face defeat, but even if he does, he would just come back from the Halls of Valhalla, where the mightiest warriors rest in Asgard.
In a fight between Adam and Thor, it would be a close match. Both of them have extreme levels of magical power. Of course, it's important to note that Thor defeated Captain Marvel, the hero that Adam usually loses to, in the 1996 DC vs. Marvel crossover comics (Ron Marz, Peter David, Dan Jurgens, and Claudio Castellini). Using his trusty hammer, Thor was able to deflect the livign lightning that turns Billy into Shazam, thus preventing him from transforming into his powered self. If Thor can defeat the hero that constantly wins against Black Adam, he can likely defeat Adam as well. Black Adam is more ruthless than Billy Batson, but the kid superhero commonly tricks Teth with the simplest tricks. Thor knows a thing or two about tricks, thanks to his brother Loki.
Just watching these two champions of DC and Marvel duke it out would be super action-packed. However, in the end, Thor has a slight edge over Black Adam. Despite having the mind of a ruler, Black Adam faces constant defeat against children. Thor, on the other hand, usually triumphs over the mightiest of his enemies. Black Adam would likely be just another name under Thor's list of victories.