Law-abiding ordinary, second-class employee (9)
I believe the answer is:
observant
'law-abiding' is the definition.
('observant' can be a synonym of 'law-abiding')
'ordinary second-class employee' is the wordplay.
'ordinary' becomes 'o' (abbreviation e.g. O-Levels).
'second class' becomes 'b'.
'employee' becomes 'servant' (I've seen this before**).
'o'+'b'+'servant'='OBSERVANT'
(Other definitions for observant that I've seen before include "attentive to detail" , "following religious practices" , "Good at noticing" , "Perceptive" , "Sharp-eyed" .)