The article studies the concept of human security (hs) as embraced by the un General Assembly and Secretary Generals, and its instrumentality in the promotion of a customary international crime of global terrorism. Such a crime exists in the opinion of the Appellate Chamber of the Special Tribunal for Lebanon. Regarding terrorism in international criminal law (icl), not in armed conflict, I maintain that the concept of hs has been pivotal in furthering the “criminalisation” of terrorism in matters peace and security. I submit that (i) that the absence of a universally agreed upon definition of (global) terrorism does not suffice to detract from the finding that such a transnational crime exists, and (ii) in addition to the various and largely agreed constitutive elements of customary law, normative paradigmatic developments – here in the case of terrorism, and in the past two decades – have significantly supported this customarisation trend.