having been emptied of air or gas

a deflated balloon

having suddenly lost confidence or optimism

the news left him feeling utterly deflated

let air or gas out of (a tyre, balloon, or similar object)

he deflated one of the tyres

make (someone) suddenly lose confidence or feel dispirited

his response deflated me

bring about a general reduction of price levels in (an economy)

the budget deflated the economy

the government deflated sharply in 1964