The word "不可开交" is formed by combining the negative adverb "不" with the modal verb "可" to create "不可", meaning "cannot", which then modifies the verb phrase "开交", where "开" means "to open or untie" and "交" means "to cross or intersect", together suggesting the act of resolving or disentangling; thus, the phrase literally constructs the idea of being unable to untie and settle, forming an idiom that describes a state of irresolvable busyness or entanglement.