schlecht schlafen

You will mostly use this in the past tense. Say Ich habe schlecht geschlafen to describe your night. It is a simple verb-adverb combination. You can add sehr (very) to make it even more dramatic. Ich habe sehr schlecht geschlafen sounds much more tragic. It fits perfectly into daily conversations.

Use it during morning coffee with friends. It is great for small talk at the office. If you are grumpy, this phrase is your best excuse. Use it when someone asks Wie geht es dir? (How are you?). It sets the tone for a low-energy day. Even doctors will ask you this during a check-up.

Avoid using this as a serious medical diagnosis. If you have chronic insomnia, use more specific terms. Do not use it to describe a nap. For naps, we use different words entirely. It is too casual for a high-stakes job interview. Unless, of course, the interviewer looks just as tired as you do.

Germans take their sleep hygiene very seriously. Many believe a cold room is the key to success. If you say you schlecht schlafen, expect advice about Lüften. That is the German art of opening windows for fresh air. They might also suggest a better Matratze (mattress). Sleep is a frequent topic of German small talk.

If you slept well, just say gut schlafen. To say you slept like a log, use wie ein Stein schlafen. If you didn't sleep at all, say kein Auge zugetan. That means you didn't close an eye. For those nights where you just couldn't drift off, use nicht einschlafen können.