Definition of downers:
(n) :
(slang) Something or someone disagreeable, dispiriting or depressing; a killjoy.
(n) :
(slang) A drug that has depressant qualities.
(n) :
(slang) A negative drug trip.
(n) :
A livestock animal that has collapsed.
(n) :
A form of industrial action in which workers down tools and refuse to work.
(n) :
(UK, slang, obsolete) A sixpence.