1. [early–mid-19C] (UK Und.) a suspicion, a degree of illegality; thus take down off, to render a (stolen) object less suspicious; there is no down, there is no risk.
2. [mid-19C+] (orig. Aus.) a prejudice against, a suspicion of; a tendency to be unkind towards; usu. as have a down on.
[mid-19C] (UK und.) sharp practice, deception.
[19C] to inform against someone.
[early 19C] (Scot. Und.) to give the alarm.