What does "giddyup" mean?

To cause a horse or similar mount to speed up.

Giddyup

/ˈɡɪdɪˌʌp/ intj, verb

intj, verb ·Rare ·Advanced level

Verb

1
To cause a horse or similar mount to speed up.
"If I could rule the world, everyone would have a gun / In the ghetto, of course, when giddy-upping on their horse"
2
To start moving or move faster; to get a move on. broadly
"But she just kept bopping up and down and telling me to giddyup, so that I had to turn and make my way properly on the stairs for fear of her pulling us both over."

Intj

"If I could rule the world, everyone would have a gun / In the ghetto, of course, when giddy-upping on their horse"

From get up or get ye/thee up.