Company from the south — one charged to hold up employment (10)
I believe the answer is:
occupation
'employment' is the definition.
(I know that employment can be written as occupation)
'company from the south one charged to hold up' is the wordplay.
'company' becomes 'co' (abbreviation).
'from the south' is a reversal indicator (in a down clue, letters go up).
'one charged' becomes 'cation' (a cation is a positively charged ion).
'to hold' means one lot of letters goes inside another.
'co' backwards is 'oc'.
'cation' going around 'up' is 'cupation'.
'oc'+'cupation'='OCCUPATION'
(Other definitions for occupation that I've seen before include "Calling" , "end of invasion?" , "the seizure and control of a foreign territory" , "Doctor, for instance" , "period of residency" .)