Fetching details from the dictionary...

unclean; dirty; unsanitary; filthy
indecent; dirty (story, money, etc.); obscene; immoral
キッチンが不潔だと食中毒になりやすい。
If the kitchen is unclean, food poisoning is more likely.
不潔な環境は病気の原因になることがある。
An unclean environment can cause illness.
彼の部屋は不潔で近づきたくない。
His room is dirty and I don't want to go near it.