They vandalise iPhone essentially over poor signal (9)

I believe the answer is:

hooligans

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'they vandalise' is the definition.
The definition suggests an adverb but the answer is not.

'iphone essentially over poor signal' is the wordplay.
'essentially' says to take the centre.
'over' becomes 'o' (cricket abbreviation).
'poor' is an anagram indicator.
The middle of 'iphone' is 'ho'.
'signal' anagrammed gives 'ligans'.
'ho'+'o'+'ligans'='HOOLIGANS'

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(Other definitions for hooligans that I've seen before include "Thugs" , "football louts" , "More than one tough" , "delinquents" , "Violent troublemakers" .)

I've seen this clue in The Telegraph.

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