WITHOUT PREJUDICE. Where an offer or admission is made "without prejudice," or a motion is denied or a suit dismissed "without prejudice," it is meant as a declaration that no rights or privileges of the party concerned are to be considered as thereby waived or lost except in so far as may be expressly conceded or decided. See Genet v. Delaware & H. Canal Co., 170 N.Y. 278, 63 N.E. 350; O'Keefe v. Irvington Real Estate Co., 87 Md. 196, 39 Atl. 428; Olson v. Coalfield School Dist. No. 16 of Divide County, 54 N.D. 657, 210 N.W. 180, 181.

A dismissal "without prejudice" allows a new suit to be brought on the same cause of action. Freidenbloom v. McAfee, Tex.Civ.App., 167 S.W. 28; McIntyre v. McIntyre, 205 Mich. 496, 171 N.W. 393, 394.

The words "without prejudice" import into any transaction that the parties have agreed that as between themselves the receipt of money by one and its payment by the other shall not of themselves have any legal effect on the rights of the parties, but they shall be open to settlement by legal controversy as if the money had not been paid. In re Bell, 344 Pa. 223, 25 A.2d 344, 350. The words "without prejudice", as used in judgment, ordinarily import the contemplation of further proceedings, and, when they appear in an order or decree, it shows that the judicial act is not intended to be res judicata of the merits of the controversy. Fiumara v. American Surety Co. of New York, 346 Pa. 584, 31 A.2d 283, 287.

Here's a few Docs on CONTRACT LAW. One is how the UCC looks at contracts, and you can compare it to the second one, which is more in layman terms.