Portmanteau of hillbilly & bully.
A person of questionable genetics (and consequently intellect) often associated with being from Appalachia (qv "Deliverance") who's also heavy into malignant narcissism and menaces/threaten people they don't agree with or like. When called out, they promptly play the victim (qv DARVO), commonly overlaps with "crybully".
By stalkingmassshooting survivors, Margorie Taylor Greene has proved herself to be a hillbully.