The full form of WYM is What you mean
WYM stands for “What you mean?”

“What you mean” is often used in messages between friends and on social media platforms. The text abbreviation expands to, “What you mean?”

Although “What do you mean?” is grammatically correct, internet users often shorten expressions and drop certain parts of speech as if they were speaking. Native speakers of English will often ask, “Watchu mean?” as a way of asking for clarification on something. Some will add in the “D” to make the correct version of “WDYM?”

This expression can be used by anyone and usually comes about when one party doesn’t understand the other.

Conversation Examples
First example

Texter 1: My life is over!
Texter 2: Really? WYM?
In this instance, the meaning is close to “Tell me more.”