nervös
nervous
Being inwardly restless, excited, or tense, often out of fear or anticipation before a specific event.
Vor dem Vorstellungsgespräch war sie sehr nervös.
She was very nervous before the job interview.

nervous
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nervous
Being inwardly restless, excited, or tense, often out of fear or anticipation before a specific event.
Vor dem Vorstellungsgespräch war sie sehr nervös.
She was very nervous before the job interview.

The adjective 'nervös' (nervous) belongs to the word family of 'der Nerv' (nerve). It describes a state in which the nerves are tense.
Laute Geräusche gehen mir auf die Nerven.
Loud noises get on my nerves.
A very common construction is 'jemanden nervös machen' (to make someone nervous). The subject is the thing that causes the restlessness, and the person is in the accusative.
Das lange Warten macht mich ganz nervös.
The long wait is making me really nervous.
When naming the cause of the nervousness, you usually use the preposition 'vor' (before / because of) with the dative, especially with future events.
Viele Leute sind vor einer wichtigen Prüfung nervös.
Many people are nervous before an important exam.
You can recognize the medical meaning from the context. It is used in technical language and in connection with medical terms such as 'System' (system), 'Störung' (disorder), or 'Leiden' (condition).
Das vegetative Nervensystem steuert viele Körperfunktionen.
The autonomic nervous system controls many bodily functions.
cool
'cool' and 'nervös' form an opposite pair when talking about a person's inner state. Here, 'cool' means that someone stays calm and composed, even when the situation is stressful. 'nervös' means that someone is inwardly restless or tense, often before an important event. 'cool' is colloquial, while 'nervös' is neutral and fits many situations.

Sie war vor der Prüfung so nervös, dass sie kaum frühstücken konnte.
She was so nervous before the exam that she could hardly eat breakfast.
Vor dem Gespräch mit der Chefin blieb ich erstaunlich cool.
Before the conversation with the boss, I stayed surprisingly cool.