(in a literary work or speech) a meaning or sense that is contrary to the original; wrong interpretation.

unlawfully earned riches; income from illegal activities.

a wrong, unsocial or immoral objective; a bad intention.

(rhet.) the usage of language or words in a language, as to give an indecent, slang sense.

infirmity - a) the state or quality of being not firm; instability; fluctuation; b) want of strength; feebleness; weakness.