One very like another regarded in ground (4,6)
I believe the answer is:
dead ringer
'one very like another' is the definition.
(a dead ringer looks like another person)
'regarded in ground' is the wordplay.
'ground' indicates anagramming the letters ('grind' the letters into a new form).
'regarded'+'in'='regardedin'
'regardedin' anagrammed gives 'DEAD-RINGER'.
(Other definitions for dead ringer that I've seen before include "Spitting image" , "Lookalike" , "Likeness" , "double" , "one looks very much like another" .)