Nasenschleim vs. Rotz vs. Schnodder
While all three words refer to the same bodily substance, the difference lies entirely in the tone and context. Nasenschleim is the polite, scientific term, Schnodder is a descriptive informal word, and Rotz is considered rude or vulgar.
Nasenschleim
B2This is the neutral, biological, and medical term for nasal mucus. You should use Nasenschleim when talking to a doctor, in a pharmacy, or in any formal situation where you need to be polite.
Der Arzt analysierte den Nasenschleim im Labor.
(The doctor analyzed the nasal mucus in the laboratory.)
Gesunder Nasenschleim ist normalerweise durchsichtig.
(Healthy nasal mucus is usually transparent.)
Dieses Medikament verflüssigt den festen Nasenschleim.
(This medication liquefies the thick nasal mucus.)
Rotz
C1This is a vulgar and often aggressive slang term for snot. Using Rotz suggests you are unrefined, very annoyed, or trying to be rude; it is not appropriate for polite company.
Wisch dir gefälligst den Rotz von der Backe.
(Wipe that snot off your cheek right now.)
Er hat seinen Rotz einfach auf den Boden gespuckt.
(He simply spat his snot onto the ground.)
Ich werde diesen grünen Rotz seit Wochen nicht los.
(I have not been able to get rid of this green snot for weeks.)
Schnodder
C1This is a colloquial, informal word often used to describe messy, runny mucus. Schnodder focuses on the slimy consistency and is heavily used in Northern Germany; it is less aggressive than Rotz but still too gross for formal contexts.
Dem kleinen Kind läuft der Schnodder aus der Nase.
(The snot is running out of the small child's nose.)
Hast du ein Taschentuch für den ganzen Schnodder?
(Do you have a tissue for all that goo?)
Er zog den Schnodder lautstark hoch.
(He sniffed up the phlegm loudly.)
Summary
Use Nasenschleim for medical or polite conversations. Use Schnodder among friends or family when describing a messy runny nose informally. Avoid using Rotz unless you intend to sound rude, angry, or very vulgar.