In real estate, right of first refusal is a provision in a lease or other agreement. It gives a potentially interested party the right to buy a property before the seller negotiates any other offers. It's typically written up before a seller puts a property on the market.
This clause allows the seller to market the home at will, but before any offers can be accepted, the seller must notify the original interested buyer who has the right of first refusal. At that point, the person with the right of first refusal can decide whether or not to buy the property. If this person declines, the seller is free to negotiate with other people who are interested.
Typically, the "interested party" is a neighbor, or neighbors, who want the right to have first shot at nearby property. Sometimes in community boat docks, ROFR allows those already owning a slip to be able to have a say in who else can own a slip. I can't rule that out as far as neighborhoods go, either.