
die Notwendigkeit
necessity
The state of something being essential, absolutely required, or unavoidable.
Der Arzt betonte die Notwendigkeit einer gesunden Ernährung.
The doctor emphasized the necessity of a healthy diet.
necessity
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necessity
The state of something being essential, absolutely required, or unavoidable.
Der Arzt betonte die Notwendigkeit einer gesunden Ernährung.
The doctor emphasized the necessity of a healthy diet.

out of necessity
Describes an action that happens not out of free will, but because of external circumstances or pressure.
Er nahm den schlecht bezahlten Job nur aus der Notwendigkeit heraus an.
He only accepted the poorly paid job out of necessity.
The word is derived from the adjective 'notwendig' (necessary). This in turn comes from 'Not wenden', which literally means to avert a hardship or emergency. A Notwendigkeit is therefore something you have to do in order to avoid hardship.
Die Notwendigkeit dieser Maßnahme ist unbestritten.
The necessity of this measure is undisputed.
'Die Notwendigkeit' (the necessity) is very often used with a genitive or an infinitive construction with 'zu' (to) in order to specify what is necessary. The structure is then 'die Notwendigkeit + genitive' or 'die Notwendigkeit, etwas zu tun' (the necessity of doing something / the necessity to do something).
Es besteht die Notwendigkeit einer schnellen Entscheidung.
There is a necessity for a quick decision.
Common verbs used with 'Notwendigkeit' (necessity) are 'bestehen' (to exist), 'erkennen' (to recognize), 'sehen' (to see), and 'betonen' (to emphasize). People often say that a necessity 'besteht' (exists).
Die Chefin hat die Notwendigkeit von Überstunden betont.
The boss emphasized the necessity of overtime.
The formulation 'aus der Notwendigkeit heraus' (out of necessity) is a fixed expression. It functions like an adverb and explains that an action was not voluntary, but forced by external circumstances.
Sie handelte nur aus der Notwendigkeit heraus, um ihre Familie zu schützen.
She acted only out of necessity in order to protect her family.
need / hardship
Notwendigkeit describes that something is essential or required due to external circumstances. In the fixed expression zur Not, Not instead means that something happens only as a last resort. Use Notwendigkeit for what is required, and zur Not when you mean a fallback solution in case there are no alternatives.

Die Notwendigkeit eines späteren Zuges ergibt sich, wenn wir den ersten verpassen.
The necessity of taking a later train arises if we miss the first one.
Zur Not nehmen wir den späteren Zug, wenn wir den ersten verpassen.
If necessary, we’ll take the later train if we miss the first one.