Definitions

1. interjection

an expression used to urge a horse to move forward, often used to encourage a reluctant horse to begin walking or to hasten its pace.

“The cowboy said ‘giddap’ to his horse and it started moving forward.”

2. verb

to urge a horse to move forward, especially by giving a loud or sharp command.

“The rider had to giddap the horse to get it to start moving.”