The word "后顾之忧" is formed by combining the character 后 (meaning "behind" or "after") with 顾 (meaning "to look back" or "to care for") to create the verb phrase 后顾, which literally means "to look back". This is then linked to the noun 忧 (meaning "worry" or "concern") using the classical Chinese possessive particle 之 (equivalent to "of" or "'s"), resulting in a compound noun phrase that directly translates to "the worry of looking back", encapsulating the concept of concerns about matters left behind.