Cross found inside among relics (7)

I believe the answer is:

mongrel

'cross' is the definition.
(thesaurus)

'found inside among relics' is the wordplay.
'found' indicates the answer is hidden within the clue.
'MONGREL' is hidden in the letters of 'inside among relics'.

(Other definitions for mongrel that I've seen before include "Mixed-breed dog" , "unlike well-bred setter, say" , "Dog of no recognisable breed" , "Cross-breed dog" , "Cur" .)

I've seen this clue in The Telegraph and The Sun.

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