1let air or gas out of (a tyre, balloon, or similar object):he deflated one of the tyres
[no object] be emptied of air or gas:the balloon deflated
2make (someone) suddenly lose confidence or feel dispirited: (as adjective deflated)the news left him feeling utterly deflated
reduce the level of (an emotion or feeling):her anger was deflated
3 Economics bring about a general reduction of price levels in (an economy):the budget deflated the economy [no object]:the government deflated sharply in 1964