This is the 2465th most frequent Arabic word.
محذرا
"محذرا" means "warning" or "cautioning."
Here, 'محذراً' is used as an adverbial participle (حال) to describe the manner in which the manager was speaking—he was speaking in a warning manner.
قال المدير للموظفين محذراً من التأخر في تسليم المشروع.
The manager said to the employees, warning against delaying the project submission.
In this sentence, 'محذراً' acts as an adverb describing the act of sending the message, indicating the warning nature of its content.
أرسل الطبيب رسالة إلى المرضى محذراً من خطورة تجاهل التعليمات.
The doctor sent a message to the patients, warning them about the dangers of ignoring instructions.
Here, 'محذرين' is a nominal participle used to describe the state of the subject (we)—they are in a state of issuing a warning.