In seconds, forget about people slain with daggers (5)

I believe the answer is:

obeli

I'm a little stuck... Click here to teach me more about this clue!

'daggers' is the definition.
(I've seen this before)

I can't explain the remainder of the clue.

(Other definitions for obeli that I've seen before include "Printer's daggers" , "signs of suspect text" , "Dagger-shaped signs" , "Marks on script" , "Textual marks" .)

I've seen this clue in The Guardian.

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