E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Hugger - mugger.
The primary meaning is clandestinely. The secondary meaning is disorderly, in a slovenly manner. To hugger is to lie in ambush, from the Danish hug, huger, huggring, to squart on the ground; mugger is the Danish smug, clandestinely, whence our word smuggle.
The king in Hamlet says of Polonius: We have done but greenly in hugger-mugger to inter himi.e. to smuggle him into the grave clandestinely and without ceremony.
Sir T. North, in his Plutarch, says: Antonius thought that his body should be honourably buried, and not in hugger-mugger (clandestinely).
While I, in hugger-mugger hid,
Have noted all they said and did.
Butler: Hudibras, iii. 3.
Under the secondary idea we have the following expressions:He lives in a hugger-mugger sort of way; the rooms were all hugger-mugger (disorderly).