怠忽 is a formal, literary verb meaning 'to neglect carelessly' or 'to be negligent', often implying a failure to fulfill duties or responsibilities due to laziness, indifference, or inattention. The character 怠 (dài) means 'lax, slack, negligent', while 忽 (hū) means 'to overlook, to disregard'. Together, they form a compound emphasizing careless omission—especially in contexts where diligence and vigilance are expected, such as official duties, medical care, or safety procedures.

This word carries a strong negative connotation and is commonly used in official documents, news reports, or serious commentary to criticize dereliction of duty. It is rarely used in casual speech and almost never with positive or neutral subjects—it always implies blameworthy negligence. While both characters can appear separately (e.g., 怠慢, 忽视), 怠忽 functions exclusively as a two-character verb and does not serve as a noun or adjective.