What exactly is smiting?!
Encarta: "Affect somebody strongly or disastrously."
Also "Fill somebody with love," but we know you're not referring to that one.
Is it just making one pay for something they've done,
Here are some examples:
"Is Israel a slave? Was he born to serfdom for him to be preyed on like this?...Have you not brought this on yourself by abandoning your God when he was guiding you on your way?" Jer. 2:14-17
"The bend their tongues like a bow; not truth but falsehood...Each one cheats his friend, never telling the truth...each wishes his neighbor peace, while in his heart plotting a trap for him. Shall I fail to punish them for this...?"
Jer. 9:4-8
"With nothing but oppression in her (the city)....from the least to the greatest, they are all greedy for gain; prophet no less than priest, all of them practice fraud... What do I care about incense imported from Sheba, or fragrant cane from a distant country? ...Your sacrifices do not please me."
(continued)
or God sending someone to eternal damnation in the bowls of hell?
"In front of this people I shall now lay obstacles for them to stumble over....Do not venture out onto the roads, for the enemy's sword is there, terror on every side....Put on a sackcloth... "
Jer. 6:6-25
This example shows a release of God's covering of protection from enemies, rather than a sending to damnation.
Does it allow for someone to repent or is it just instantaneous beatdown?
The smite passages are warnings. Some of them were not carried out, because they were usually "If you don't stop this..."
"From the day your ancestors left Egypt until today, I have sent you all my servants the prophets, persistently sending them day after day. But they have not listened to me." Jer. 7:25, 26
"Come back..I shall give you shepherds after my own heart, who will pasture you wisely and discreetly." Jer. 3:14
Does one die when smited or do they live?
Sometimes. But they get plenty of warning. One dies from the electric chair, but it prevents multiple unchecked deaths and injustices. (I'm not getting into criminal justice debates here, just trying to show some logic in God's justice system.)
I sometimes panic and cringe when I read the smite passages--a natural reaction to making sure I'm not the one getting punished. But these were also a comfort to me at a time when spiritual leaders were abusing their flock, and the people had no recourse. Then it's nice to know that God sees what's going on and is willing to take the underdog's side.