Here's why:
* Grammatically incorrect: "Chi" (吃) means "to eat", and "Wu" (午) means "noon". While the literal meaning is clear, the grammatical structure is incorrect.
* Redundant: The act of eating is generally associated with a specific time. Therefore, saying "eat noon" is redundant.
Instead, you'd likely use these phrases to express eating lunch:
* 吃午饭 (chī wǔfàn): "Eat lunch"
* 吃中饭 (chī zhōngfàn): "Eat midday meal"
Let me know if you have any other Chinese phrases you'd like to understand!