Disrespectful rough dismissing Conservative (4)

I believe the answer is:
rude
'disrespectful' is the definition.
(I've seen this in another clue)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for rude that I've seen before include "discourtesy" , "Base" , "Uncultivated" , "'Bad-mannered, discourteous (4)'" , "Impudent" .)
