This "Hippy เป็น คุณศัพท์ กล่าวถึงบางคนผู้มีสะโพกผายใหญ่กว้าง" is new to me. I really have not heard "hippy" in other than the usual noun for 'hipster". I think I have seen more of "hippy" rather than "hippie". The usual rule for plural dressing is hippy --> hippies.

She is hip. = She is trendy = She follows the latest fashion or trend. ('hip' here is adjective.)