This is an original WWII-era German Government Official's Dagger.

Overall length in scabbard is ~16"; overall length out of scabbard is ~14-1/2".
Blade length is ~10-1/4"; hilt is 4-1/4" in length.

Blade is marked ALCOSO over ACS (scales) over SOLINGEN (see image below); this trade name is abbreviated from Alexander Coppel of Solingen, Germany.

Hilt has an eagle-head pommel cap. All metal parts appear to be silver-plated. Winged eagle on the cross-guard, depicting the usual Nazi motif for this dagger type.

Scabbard is ~11-3/4" in length and upper band depicts a oak-leaf motif, as does the lower section of the scabbard; ball finial drag. Scabbard is actually from a "LUFTWAFFE 2nd Model dagger."