汚す （よごす、けがす） To Make Dirty, To Make Something Dirty
汚れる （よごれる、けがれる） To Get Dirty, To Get Polluted, To Become Dirty
濁す （にごす） To Make Muddy, To Make Cloudy, To Speak Ambiguously, To Speak Vaguely
濁る （にごる） To Become Muddy, To Become Impure, To Become Cloudy