A jokerless hand is exactly what it sounds like: a hand built entirely from the tiles you actually need, with zero jokers standing in for anything. On the NMJL card, hands marked with a "C" (concealed) can't use jokers at all — every other hand allows them, unless you're deliberately declining to use one you could.
Playing jokerless is harder and riskier. You lose the safety net of swapping in a joker for a tile you can't complete, which means a jokerless hand takes longer to build and is more likely to get stuck. But it pays off: most tables score jokerless hands higher, and going out jokerless off a wall game is one of the more satisfying ways to win a hand.
If you're newer to the game, don't chase jokerless on purpose yet. Learn the card first. The bonus points will still be there once you've got a few games under your belt.
New to the table? Start with mahjong terms explained or our step-by-step guide to American mahjong.