During night-time it’s a common site to see many house lizards perched on the wall and they also squeak. There is a superstition in Kerala, that if you hear a lizard squeak and if you are thinking something then it will come true. But sad for me, such a thing has never happened.
Lizard’s Word as an idiom means not to take the person who says, seriously.
Example: Doomsday prophecies could be taken as a lizard’s word.
My friend is unreliable and I take his words as being Lizard’s words.