empty, exaggerated, or pretentious talk or writing:
His report on the company's progress was just so much hot air.
Origin
1835-45 for literal sense
Examples from the web for hot air
The point was rhetoric is bull as it is it as empty as the hot air of opinion.
hot air rises, vents out the top of the shower stall and sucks cooler air in from the bottom.
The anti-icing system prevents ice from forming by blowing hot air from within the compressor of the engine.
hot air rises, so even if you heat the top of the house, you still need to run the furnace to heat the lower floors.
If using geothermal, try radiant water heat instead of forced hot air.
Early designs grew out of the pressurized suits worn by trailblazing pilots in hot air balloons and airplanes.
Over the years his birthday gifts have sent him parasailing, on hot air balloons rides, and zip-lining through canyons.
Attic fans draw hot air out of your house to help cool it.
The aisles will be sealed with plastic sheets so that the cooling systems don't work overtime cooling the hot air.
Get the same bird's-eye view from the basket of a hot air balloon.
British Dictionary definitions for hot air
hot air
noun
1.
(informal) empty and usually boastful talk
Slang definitions & phrases for hot air
hot air
noun phrase
Nonsense; pretentious talk; bold and deceitful absurdities; baloney, bullshit: The Jefferson family tree will never be blown down by any hot air from me
Pomposity and vanity; bombast: The old fraud talks a lot of hot air(1900+)
Empty, exaggerated talk, as in That last speech of his was pure hot air. It is also put as full of hot air, as in Pay no attention to Howard—he's full of hot air. This metaphoric term transfers heated air to vaporous talk. [ Late 1800s ]