lowdown

Etymology

Compound adjective of low + down in the sense of "humble" recorded in the 1540s, in the sense of "vulgar, far down the social scale" in 1888. Recorded as a noun in 1915 in the slang sense of secret or inside information.

noun

1. inside information, the story or truth.
   All the reporters hoped to be the first to get the lowdown on the celebrity's marriage plans.
   here's the lowdown
   to give somebody the lowdown
2. A lowlife, a despicable person.

adj

1. Unfair; shameful.
   lowdown tactics
2. down low; purporting to be heterosexual while engaged in sex with men.