die Utopie
pipe dream
An idea or plan that is considered completely unrealistic and impossible to carry out.
Sein Vorschlag, das Problem in einer Woche zu lösen, ist reine Utopie.
His proposal to solve the problem in one week is a pure pipe dream.

utopia
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pipe dream
An idea or plan that is considered completely unrealistic and impossible to carry out.
Sein Vorschlag, das Problem in einer Woche zu lösen, ist reine Utopie.
His proposal to solve the problem in one week is a pure pipe dream.

The related adjective is 'utopisch' (utopian). It describes an idea or plan as unrealistic or as belonging to a utopia.
Seine Pläne für die Zukunft klingen ziemlich utopisch.
His plans for the future sound pretty utopian.
When 'Utopie' (utopia) is used to dismiss an idea as unrealistic, it often appears with adjectives like 'rein' (pure) or 'bloß' (mere). Phrases like 'Das ist reine Utopie' (That is pure utopia / a pure pipe dream) are very common.
Ein Leben ohne Arbeit ist für die meisten Menschen eine reine Utopie.
A life without work is a pure pipe dream for most people.
The meaning of an ideal social order is found mainly in philosophical, literary, or political texts. Often, the type of utopia is described more precisely, e.g. 'eine soziale Utopie' (a social utopia) or 'eine technische Utopie' (a technological utopia).
In seinem Roman entwirft der Autor die Utopie einer perfekten Welt.
In his novel, the author designs the utopia of a perfect world.
reality
'die Realität' and 'die Utopie' are opposites when it comes to what is real and what is only imagined. 'die Realität' describes what actually exists or what circumstances are really present. 'die Utopie' describes an ideal idea or a plan that seems unreachable or impossible to carry out in reality. 'Utopie' can sound positive when it refers to a perfect model, but also critical when a plan is unrealistic.

Eine Stadt ohne Verkehr und Lärm bleibt für viele Menschen eine Utopie.
For many people, a city without traffic and noise remains a utopia.
In der Realität haben viele Familien nicht genug Zeit für lange Gespräche.
In reality, many families do not have enough time for long conversations.