The Amarna form renders Egyptian pꜣ mhr “the warrior”, whose former element is the New Egyptian definite article and latter, a West Semitic word derived from *mhr ‘to be smart, capable, able’ (Hoch 1994:147–149).
In EA 366:34, as a gloss to ZAG!.ḪI<.A>-ši (Rainey 1978:34‒35, 98).
For a different evaluation v. van Soldt 1997, who prefers to relate up-sí- to Ugr. ˁbs/ˁps ‘landmark, boundary’ (DUL 174)