whatsay adverb 2exclamation 1 adverb2 •(slang) Used to introduce a proposalWhatsay to splitting the cost with me?Whatsay we split the cost? •(no longer used) What sayWhatsay you, my Lord?Whatsay our friends to our new allies? exclamation1 •(slang) What did you say?"Did you finish mowing the lawn?" / "Whatsay?"