I don't like the people who are untidy. The underlined part is -

Who are untidy এখানে relative pronoun who আছে so it is a relative clause.যা I don't like বাক্যের মাধ্যমে সম্পুর্ণ হয়েছে।
- দুটি সমজাতীয় principal clause যদি কোনো Co-ordinating conjunction(and, or, but, so) দিয়ে যুক্ত হয় তখন তাকে Co ordinate clause বলে।
- example: I took no notice of him, so he flew into rage.

Source: Advanced Learner's Grammar and Composition by Chowdhury and Hossain