verb

knock or bring to the ground.

175 enemy aircraft had been downed

knock down,knock over,knock to the ground,throw to the ground,bring down,bring to the ground,fell,topple,prostrate,tackle,rugby-tackle,trip up,deck,floor,flatten

noun

a period of unwelcome experiences or negative mood.

there had been more downs than ups during his years at the company

setbacks,upsets,reverses,reversals,reversals of fortune,downturns,mishaps,strokes of ill luck,strokes of bad luck,accidents,shocks,vicissitudes,crises,catastrophes,tragedies,calamities,trials,crosses,knocks,burdens,blows,buffets,glitches,(double) whammies,knock-backs,foils,fit of depression,period of despondency,the blues,the dumps,one’s black dog,a low,the blahs,a funk,a blue funk,the mopes,dolour,the megrims