zumachen

Since it is separable, you split it up. You say Ich mache die Tür zu. The zu sits right at the end like a little anchor. In the past tense, it becomes zugemacht. You can use it for almost anything physical. Windows, doors, bags, and even your own eyes. It is simple, effective, and very common. Just remember to put the zu at the very end of your thought.

Use it when you are at home with friends. Use it when you are at a shop that is about to close. It is perfect for telling someone to zip up their jacket. You will hear it at the doctor's office too. They might say Machen Sie die Augen zu (Close your eyes). It is the bread and butter of daily German life. If you are cold, just ask Kannst du das Fenster zumachen? Everyone will understand you perfectly.

Avoid it in very formal or legal documents. In a contract, use schließen instead. Don't use it for 'closing a deal' in a high-stakes boardroom meeting. It might sound a bit too casual there. Also, don't use it for 'closing a bank account.' That usually requires the word auflösen. It is for physical things, not abstract concepts. Keep it for things you can actually move with your hands.

Germans have a complex relationship with windows. There is a famous love for *Stoßlüften* (shock ventilation). This means opening windows wide for five minutes. But Germans also fear the *Durchzug* (draft). You will often hear a sudden Mach bitte zu! when someone feels a breeze. It is a word that keeps the peace in German households. It is practical, direct, and very efficient.

The direct opposite is aufmachen (to open). If you want to sound slightly more sophisticated, use schließen. If you are locking something with a key, use abschließen. But for 90% of your daily life, zumachen is the winner. You might also hear festmachen, which means to fasten something tightly. Stick with zumachen for now, and you will be fine.