the sport or pastime of flying in a balloon

he took up ballooning in 1907

a ballooning accident

(of a number or amount) rapidly increasing

the ballooning costs of higher education

the ballooning numbers create stress on the infrastructure

the government is blamed for the ballooning debt

swell out in a spherical shape

the trousers ballooned out below his waist

(of an amount of money spent or owed) increase rapidly

the company's debt has ballooned in the last five years

(with reference to a ball) lob or be lobbed high in the air

the ball ballooned into the air

travel by hot-air balloon

he is famous for ballooning across oceans