1.  to move restively sidewise or backward instead of forward, as an animal in harness; balk.
2.  to balk at doing something; defer action; procrastinate.
-noun
3.  a horse or other animal that jibs

4. When followed by or connected to jabber
Jibber jabber means verbal commotion, or talking in a way that annoys anyone present. and can be replied to with the phrase "quit your jibber jabber margo you fool"