What does tu estudiar means?

"Tu estudiar" is grammatically incorrect in Spanish. It should be either:

* "Tú estudiar": This means "You to study" or "You studying" in the informal "tú" form. It's usually used as a command or an instruction.

* "Tu estudio": This means "Your study" or "Your studies" in the informal "tu" form.

Let me know if you have any other Spanish phrases you need help understanding!