das Genick
nape / neck
The back part of the neck; the nape.
Durch die kalte Zugluft ist mein Genick ganz steif geworden.
The cold draft made my neck go completely stiff.

nape / neck
Loading your saved state.
nape / neck
The back part of the neck; the nape.
Durch die kalte Zugluft ist mein Genick ganz steif geworden.
The cold draft made my neck go completely stiff.

You can tell from the context whether the literal or figurative meaning is intended. If people are talking about the body, pain, or physical actions, it means the neck. If it is about failure, finances, a career, or projects, the figurative meaning of “ruin” is intended.
Er massierte sich das Genick, weil er den ganzen Tag am Computer saß.
He massaged the back of his neck because he had been sitting at the computer all day.
In its literal meaning, “Genick” (nape/neck) is often connected with physical actions or conditions. Typical expressions are “ein steifes Genick haben” (to have a stiff neck), “sich das Genick verrenken” (to strain/twist one’s neck), or “jemanden am Genick packen” (to grab someone by the scruff of the neck).
Vom Schlafen im Sessel hatte er ein ganz steifes Genick.
From sleeping in the armchair, he had a completely stiff neck.
The idiom “jemandem das Genick brechen” (to break someone’s neck) has a fixed structure. The cause of the failure is the subject of the sentence, while the person or thing that fails is in the dative.
Die hohen Kosten für das Projekt haben der Firma das Genick gebrochen.
The high costs of the project broke the company’s neck.
neck / throat
'der Hals' and 'das Genick' both refer to an area between the head and the body. 'der Hals' is more general and can mean the whole connecting part, often also the front side with the throat. 'das Genick' more specifically means the back of the neck, the nape area. Learners may confuse the words because both belong to the same body part. A practical rule is: for a sore throat, swallowing, or speaking, you usually say 'Hals'. For pain at the back of the neck or a movement of the head, 'Genick' often fits better.

Nach der langen Fahrt ist mein Genick ganz steif.
After the long drive, my neck is completely stiff.
Nach dem kalten Wind tut mir der Hals weh.
After the cold wind, my throat hurts.