Working copper spotted escorting force regulars (8)
I believe the answer is:
occupied
'working' is the definition.
(thesaurus)
'copper spotted escorting force regulars' is the wordplay.
'copper' becomes 'Cu' (Cu is the chemical symbol for copper).
'spotted' becomes 'pied-' (I've seen this in another clue).
'escorting' says to put letters next to each other.
'force regulars' becomes 'oc' (I can't explain this - if you can you should believe this answer much more).
'cu'+'pied'='cupied'
'cupied' after 'oc' is 'OCCUPIED'.
Can you help me to learn more?
(Other definitions for occupied that I've seen before include "Full; working" , "Inhabited, held" , "Employed" , "Filled or in use" , "tied up" .)