Business upset with human resources over last office pigment (5)
I believe the answer is:
ochre
'pigment' is the definition.
(ochre is a colour)
'business upset with human resources over last office' is the wordplay.
'business' becomes 'co' (short for company).
'upset' says the letters should be written backwards.
'with' says to put letters next to each other.
'human resources' becomes 'HR'.
'over last office' becomes 'e' (I can't justify this - if you can you should give a lot more credence to this answer).
'co' reversed gives 'oc'.
'oc'+'hr'+'e'='OCHRE'
Can you help me to learn more?
(Other definitions for ochre that I've seen before include "Brown" , "Mineral pigment; chore (anag.)" , "Yellowish-orange colour" , "Yellow-red mineral from iron oxide used as pigment" , "An orangey pigment" .)