Adam is able to copy any abilities he is able to see. On top of that, the abilities he copies are superior to the original, so if Goku does a kamehameha, Adam would copy it and it would be stronger than Goku's. He able to copy abilities like time manipulation and his body reshapes itself to fit the technique (as seen when his hands altered shape and size to perform the snakes god attack). Adam also can copy multiple techniques as he copied all of Zeus's moves and then used them, so its not a "one at a time copy" copy ability.
The only time Adam had trouble was after copying Zeus ultimate straight punch because it was putting massive strain on his nervous system (Ears, eyes etc..). And that was only after performing it a many times over and Zeus wasn't giving Adam time to rest with a constant barrage of attacks. So unless he is having Kiaoken (assuming it also does damage to the nervous system) on for a extremely long time or Goku forcing him to stay in it for a long period of time, then Adam would be fine.
Even if Goku manages to kill Adam with one of his attacks, Adam would still fight because of his willpower, as he died sometime in the exchange of blows with Zeus but didn't stop fighting until Zeus was defeated.
Adam also has extremely good dodging skills, he was only hit after his eyes gave out. So it's likely Goku has a slim change of hitting him too.
