Hotline fails, something from the Stone Age (7)

I believe the answer is:

neolith

'something from the stone age' is the definition.
(a Neolithic weapon or object)

'hotline fails' is the wordplay.
'fails' indicates anagramming the letters (I've seen 'failed' mean this).
'hotline' with letters rearranged gives 'NEOLITH'.

(Other definitions for neolith that I've seen before include "Prehistoric stone tool - hotline (anag)" , "Primitive stone implement" , "Ancient stone implement" , "maybe used at Stonehenge?" , "Old stone tool" .)

I've seen this clue in The Guardian.

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