It is a common phrase used to ask someone about their plans or intentions.
Here's a breakdown of the words:
* Que: This is the interrogative word meaning "what" or "which."
* Vas: This is the informal form of the verb "ir" (to go), conjugated in the second person singular (you).
* a: This is the preposition "to."
* hacer: This is the verb "to do" or "to make."
Together, these words form the question "What are you going to do?"