Answer: hup

AnswerCrossword Clue
HUPMarch sound
HUPGiddap!
HUPWord to urge a horse: Dial.
HUPDrill sergeant's cry.
HUPWord to urge on a horse.
HUPWord used to urge on a horse.
HUPRelative of "giddap."
HUPCommand to a horse
HUPDrill-sergeant's word
HUPWagoner's command
HUP"Giddap!"
HUPMarch starter
HUPMarch syllable
HUP"..., two, three, four..."
HUPDrill sound
HUPDrill sergeant's call
HUPMarch word
HUPOne in the Army
HUPDrillmaster's call
HUP"Two, three, four" lead-in
HUPDrill sergeant's bark
HUPStart of a drill sergeant's count
HUP"....., two, three, four"
HUP"..., two, three, four!" (marching words)
HUP"..., two, three, four!" (marching shout)
HUPDrill instructor's syllable
HUPCadence call
hupto go faster (by shouting hup to a horse)
hupused to mark a marching cadence
HUPMarching cadence start
HUP"..., two, three, four" (military march cadence)
HUPCommand to Trigger
HUPCadence-call opener
HUPDrillmaster's word
HUP"..., two, three, four ..."
HUPMarch beginning
HUPMarch opener?
HUPMarching start?
HUPDrill sergeant's "one"
HUPDrillmaster's bark