Hugger-mugger
Part of speech: noun
Definition: Secrecy. Disorder.
Part of speech: adjective
Definition: Secret, clandestine. Disorderly, chaotic, confused.
Part of speech: adverb
Definition: Secretly. Confusedly, in a muddle.
Hush-hush
Part of speech: adjective
Definition: Secret, not spoken of (or spoken of only in hushed whispers between insiders).