This is probably not the best definition, but....
Nutpeddling is when someone will only put money in the pot when they have one of the best possible hands available on the board -- e.g., trips. straight, or flush. It refers more to post-flop play than pre-flop.
If you are playing with a table full of nut-peddlers, it sucks because you will almost never get any action with 2-pair or TPTK unless you are beat. Basically, top two pair won't take down a big pot. Occassionaly people will make mistakes by giving you odds to draw, but this is rarely the case. It's more likely that they push all-in if they have top set or the nut straight.
One way to get an edge at these tables is to ovebet the pot a bit. For example, if you have top set and there is a straight draw or a flush draw on the board, you can bait one or more of the draws into chasing their hand. The catch is to bet enough so that the pot odds don't justify the call, but they will often call anyway. While profitable, this can be somewhat boring because you have to wait until you have a good hand (trips or better) and your opponent has a draw to a better hand that hopefully doesn't hit. My personal favorite is straight over trips.... this pays off well. Connectors (esp. suited) are your friend.
Another way to beat nutpeddlers is to nickle and dime them as a LAG. That, however, is anothe topic.
FWIW, I recently complained that the Party tables seem to fill up with nut-peddlers during the bonus time. Boring.