(1):

(n.) A state of privacy; secrecy.

(2):

(n.) The absence of light; blackness; obscurity; gloom.

(3):

(n.) A state of ignorance or error, especially on moral or religious subjects; hence, wickedness; impurity.

(4):

(n.) Want of clearness or perspicuity; obscurity; as, the darkness of a subject, or of a discussion.

(5):

(n.) A state of distress or trouble.