متأخر

In a sentence

• وصلت إلى الاجتماع متأخرًا.

  I arrived at the meeting late.

  Here, 'متأخرًا' is an adverb describing the manner in which the subject arrived.

• الشخص المتأخر يجب أن يعتذر.

  The tardy person must apologize.

  In this sentence, 'المتأخر' is used as an adjective modifying 'الشخص' to describe someone who is late.

• لا تصل متأخرًا إلى المدرسة.

  Do not arrive late to school.

  Here, 'متأخرًا' again is used as an adverb to describe the advised timing for arriving at school.