획일성이 · 획일성을
uniformity, conformity, one-size-fits-all nature
Example
교육의 획일성이 학생들의 창의력을 떨어뜨린다는 비판이 있어요.
Some criticize the uniformity of education for stifling students' creativity.
Word parts
획 draw a line+일 one+성 quality
Literally 'drawn into one line': everything made the same.