mupwI' yI'uchtaH
Keep holding the hammer! TKW

HoSghaj; mupwI' rur
powerful as a hammer [common simile] KGT
(TKW 120):  the hammer is a symbol of power to Klingons

(KGT 129):  for a Klingon, a hammer is a symbol of power. The phrase HoSghaj; mupwI' rur ("powerful as a hammer") is based on this notion.

Derived from mup "impact,  strike":

pay' HIvDI' lo'wI' pagh mupDI' QIHchu' bIH
[They] provide a damaging surprise attack or give a devastating backhand stroke. SP2

muptaHvIS tay''eghmoH QeHDaj Hoch
All his rage focused in one blow  (PB)

pe'vIl mupmeH betleH Qach
The Mighty Blow of the Bat'leth (PB; title)

SEE ALSO:

mupwI'Hom       mallet (for striking a musical instrument) (n)
Hut'In          nail (n)
wIl             spike (n)