This is the 11569th most frequent Russian word.
дурной
"Дурной" means "bad," "foolish," or "wicked," depending on context.
Here, 'дурной' is used to describe an action as foolish or unwise.
Он сделал дурной поступок.
He committed a foolish act.
In this case, 'дурной' characterizes the mannerisms as bad or improper.
У него дурные манеры.
He has bad manners.
Here, 'дурной' qualifies the smell as bad or unpleasant.