This term was made popular by Mobb Deep in the song "Shook Ones" when they called whack niggahs out who were "Scared to death, scared to look, you shook, cuz ain't no such thing as Halfway Crooks"
'cause ain't no such things as halfway crooks"
Shook Ones Pt. II Mobb Deep
Note: Eminem uses this verse in a rap battle against Papa Doc in 8 Mile
Used as a diss in freestyleraping to describe someone who claims to be a thug or hard but is very much the opposite.
Guy 2- "Hell no he ain't! He's a halfway crook"