The word "堪忧" is formed by combining the character "堪", meaning "to bear" or "to be worthy of", with "忧", meaning "worry" or "concern". This creates a compound where "堪" functions as a modifier indicating worthiness, and "忧" as the object of that worthiness, resulting in a term that literally means "worthy of worry" and conveys the sense of being worrisome or causing concern.