The term "unlawful enemy combatant" was initially coined in a 1942 US Supreme Court decision, as shorthand referring to persons captured while participating in armed conflict without the required authorisation. The notion that a combatant (who by definition is someone authorised to participate directly in hostilities) can be simultaneously unlawful raises complex legal questions. Not surprisingly, the category "unlawful enemy combatant" does not appear in any of the international humanitarian law (IHL) treaties. It is therefore alarming that, since its reincarnation under the Bush administration, it has crept into legal literature, military manuals and case law but has yet to be defined by international agreement. Over the last century and a half, armed conflicts have played out in predominantly civilian locations, giving rise to greater intermingling of civilians with combatants. The IHL principle of distinction between lawful combatants and civilian was, and still is, intended to assist commanding officers in making legally defensible targeting decisions. However, the reality is that these supposedly clear-cut categories cannot provide clear-cut answers in modern international armed conflicts that are regulated by conventions which never envisaged the degree of civilian involvement in modern armed conflict. This legal confusion has given rise to misguided ideas - that civilian status can be forfeited or lost, and has fuelled the use of terms such as "unlawful enemy combatant", an issue that is critically explored in this contribution.