backstair vs hugger-mugger

backstair

• clandestine, secret or furtive 

• The backstairs (stairs at the rear of a building). 

hugger-mugger

• Secret, clandestine, sly. 

• Disorderly, chaotic, confused. 

• To meet or act secretly. 

• Disorder. 

• Secretly. 

• Confusedly, in a muddle.