One breaking stone ground at that place (2-4)
I believe the answer is:
on-site
'one breaking stone ground at that place' is the definition.
Both the definition and answer are adjectives. Maybe you can see an association between them that I don't see?
'one breaking stone ground' is the wordplay.
'one' becomes 'i' (Roman numeral).
'breaking' means one lot of letters goes inside another.
'ground' is an anagram indicator ('grind' the letters into a new form).
'stone' with letters rearranged gives 'onste'.
'i' put inside 'onste' is 'ON-SITE'.
Can you help me to learn more?
(Another definition for on-site that I've seen is " At a particular location".)