This is the 6167th most frequent Arabic word.
يضر
"يضر" means "to harm" or "to damage."
Here, 'يضر' means 'harms', describing the negative effect excessive sugar consumption has on health.
تناول الكثير من السكر يضر بالصحة.
Consuming a lot of sugar harms health.
In this sentence, 'يضر' signifies 'harms', referring to the detriment caused by urban pollution to the environment.
التلوث في المدن الكبرى يضر بالبيئة.
Pollution in major cities harms the environment.
The word 'يضر' is used metaphorically here to describe damage to interpersonal professional relationships caused by lack of punctuality.