Definition - What does Handshake Deal mean?
A handshake deal is a verbal agreement that stands in lieu of a written contract for the provision of some type of service between two parties. The deal has to be witnessed by a third party and followed up by some type of documentation, such as an email, for it to be considered valid.
If the person suing over a handshake deal does not have any proof to back the existence of the deal, it would not be upheld as legally binding.
Justipedia explains Handshake Deal
Many people do not feel that a handshake deal holds the same contractual binding as a signed contract, and might try to change the agreed terms if the other person is not able to call upon some type of proof that an agreement was made.