I read all of the other definitions, they are all wrong! 'LOP' is used as a commonplace description in the California Department of Corrections since at least the 80's. So many inmates over the years going home have made it popular terminology on the street too. As an inmate, 'LOP' status means 'Loss Of Privileges', a result of said inmate not following policy... Among the correctional staff, it means "Low Overall Performance"... though no officer or supervisor I ever asked, could ever verbalize what it meant or stood for! So, I figured it out perfectly for that environment!
Inmate... "Bitch, dat's the last time you pull dat shit on me and don't cook! You on LOP status til you gain some respect fo' me! Get me a Hennessy!"
C/O... "What a LOP! He didn't hand out the TP (toilet paper) on Third Watch!