Fem. nāgirtu.
Cf. Gez. nagara ‘to say’ and its Ethiopian cognates (Kogan 2015: 340: a non-attested *nagāru ‘to announce’, but nugguru ‘to denounce’ as well as in its nominal derivates munaggiru ‘informer’ (CAD M₂ 198) and taggirtu ‘denunciation’ (CAD T 38). Hard to separate from Sum. nimgir with the same meaning, and a borrowing from Akk. to Sum. appears more likely than vice versa (Edzard 1981:284‒285, Steiner 2003:634, Sassmannshausen 1995:91‒92, contra Sommerfeld 2006:64)
The origin of Akk.-Ugr. *nāgir- ‘herald’ is uncertain. Huehnergard’s assertion “the word nāgiru ‘herald’ is not attested in any Semitic language other than Akkadian” (1987a:94) is nevertheless correct (contra J. Sanmartín).