Dirty profession, Jack going on location (7)
I believe the answer is:
obscene
'dirty' is the definition.
(similar in meaning)
'profession jack going on location' is the wordplay.
'profession jack' becomes 'ob' (I can't justify this - if you can you should give a lot more credence to this answer).
'going on' means one lot of letters go next to another.
'location' becomes 'scene' (scene can mean a location or area).
'ob'+'scene'='OBSCENE'
Can you help me to learn more?
(Other definitions for obscene that I've seen before include "not decent" , "Lewd - offensive" , "coarse!" , "One's CBE (anag)" , "Rude" .)