A hypothetical case is one you invent in order to think with — it has not happened and it may never happen. Say you found a wallet on the pavement with five hundred pounds in it: the wallet does not exist, and the question is what you would do.
Lawyers, teachers and interviewers live on these, and the noun behind the adjective is hypothesis; in American English an invented case is itself called a hypothetical. People reach for hypothetically speaking or purely hypothetical when they want to ask something without admitting it is about them. In science the word turns dry rather than playful: a hypothetical particle is one the theory requires and nobody has yet found. Hypothetical does not mean false — it means put forward for the sake of the argument, and the argument may end by proving it true. It pairs with would: in a hypothetical world where nobody sleeps, what would the shops do?
1adjectivehypotheticalImagined or suggested for the sake of argument rather than real.
“Give me a hypothetical example so I can see how the rule works.”
synonyms: supposed, imagined
2adjectiveproposedProposed by a theory but not yet observed.
“The model depends on a hypothetical ninth planet.”
3nouninventedAn invented situation put forward for discussion, chiefly in American English.
“Let me put a hypothetical to you.”
HYPO-thetical → HIGH
Hold your hand up high above your head and say: suppose the water came up to here. It never did. Everyone looks at your hand anyway and starts arguing about the boats.
hooks ontohigh
Hypothetical came from Ancient Greek ὑποθετικός, which English took over as a finished adjective. It still travels with its noun, hypothesis, and the two behave like a matched pair wherever an argument needs a starting assumption.
Ancient Greek
ὑποθετικός
English, today
hypothetical
From Ancient Greek ὑποθετικός.
Etymology from Wiktionary, CC BY-SA