im·pure 
/ɪmˈpjuɚ/ adjective
[
more impure; most impure]
: not pure: such as
a : dirty,
unclean ▪ impure water b : mixed with something else that is usually not as good
▪ an impure chemical ▪ selling impure drugs c : sexual in a way that is considered morally wrong
▪ impure thoughts
