Appearance of one working oppressed by phobia (10)
I believe the answer is:
complexion
'appearance of one working oppressed by phobia' is the definition.
'complexion' can be an answer for 'appearance' (complexion is a kind of appearance). I'm not sure about the 'of one working oppressed by phobia' bit.
'appearance of one working' is the wordplay.
'appearance of' becomes 'complex' (I am not sure about this - if you are sure you should believe this answer much more).
'one' becomes 'I' (Roman numeral).
'working' becomes 'on' (on can mean working or activated).
'complex'+'i'+'on'='COMPLEXION'
Can you help me to learn more?
(Other definitions for complexion that I've seen before include "Nature" , "Look" , "character" , "Skin's tone and texture" , "Skin tone" .)