Jack-o-lard 

Someone who persistently hounds your actions to gain an advantage but does nothing once he obtains it.

That jack-o-lard beat me out of a promotion.

Jack-o-lard by RMatrix September 14, 2021

Jacko-lard 

Someone who persists at hounding your every move to gain an advantage but does nothing once he obtains it.

That jacko-lard beat me out of a promotion using my skills then quit his job.

Jacko-lard by RMatrix September 14, 2021