The most common and most likely answer to this crossword clue is the 9 letter word HEDGEHOGS
I've seen this crossword clue in The Guardian
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Buddy explains!
The straight part
We know that "1 down 24?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case 1 down 24? = hedgehogs.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does HEDGEHOGS mean?
HEDGEHOGS noun- A small mammal, of the family Erinaceidae or subfamily Erinaceinae (spiny hedgehog, the latter characterized by their spiny back and often by the habit of rolling up into a ball when attacked.)
- Any of several spiny mammals, such as the porcupine, that are similar to the hedgehog.
- A type of moveable military barricade made from crossed logs or steel bars, laced with barbed wire, used to damage or impede tanks and vehicles; Czech hedgehog.
- A spigot mortar-type of depth charge weapon from World War II that simultaneously fires a number of explosives into the water to create a pattern of underwater explosions intended to attack submerged submarines.
- A type of chocolate cake (or slice), somewhat similar to an American brownie.
- A form of dredging machine.
- Certain flowering plants with parts resembling a member of family Erinaceidae
- The edible fungus Hydnum repandum.
- A kind of electrical transformer with open magnetic circuit, the ends of the iron wire core being turned outward and presenting a bristling appearance.
- A way of serving food at a party, consisting of a half melon or potato etc. with individual cocktail sticks of cheese and pineapple stuck into it.
- To make use of a hedgehog barricade as a defensive maneuver.
- To array with spiky projections like the quills of a hedgehog.
- To curl up into a defensive ball.