1To blow, as the wind does — air moving and hitting people or things.
海から強い風が吹いている。
A strong wind is blowing in from the sea.
窓を開けたら冷たい風が吹いてきた。
When I opened the window, a cold breeze blew in.
冬になると北風が激しく吹く。
In winter the north wind blows hard.
2To blow with one's breath — e.g. blowing on hot food to cool it, blowing out a candle, or puffing air out.
熱いスープに息を吹いて冷ます。
I blow on the hot soup to cool it down.
彼女はロウソクを吹いて火を消した。
She blew out the candle.
赤ちゃんの頬にそっと息を吹く。
Gently blow a breath onto the baby's cheek.
3To play a wind instrument, or to blow a whistle/trumpet to sound it.
彼は休日にサックスを吹く。
He plays the saxophone on his days off.
小学校で子どもたちがリコーダーを吹いている。
The children at elementary school are playing recorders.
審判が試合終了のホイッスルを吹いた。
The referee blew the whistle to end the match.
4To emit or spout smoke, steam, fire, etc. — to spew out forcefully (used almost interchangeably with 噴く).
火山が黒い煙を吹いた。
The volcano spewed out black smoke.
蒸気機関車は煙を勢いよく吹き上げながら走る。
The steam locomotive runs while forcefully puffing out smoke.
5To sprout or put forth buds — used of plants producing new shoots.
春になって木の枝が芽を吹いた。
Spring came and the tree branches put forth buds.
芽が吹き始めたので、もうすぐ花が咲くだろう。
The buds have started to sprout, so the flowers will probably bloom soon.
6To appear on a surface or form a coating — e.g. a powdery residue, salt, or rust forming on a surface.
古い陶器の表面に白い粉が吹いている。
A white powder has come out on the surface of the old pottery.
冬は肌が乾燥して粉を吹くことがある。
In winter, skin can get dry and flake (literally, "blow powder").
7Slang: to burst out laughing — to suddenly crack up, unable to hold it in.
そのコントに思わず吹いた。
I couldn't help cracking up at that comedy sketch.
教室で彼の一言に吹きそうになったが、必死でこらえた。
I almost burst out laughing at his remark in class, but I held it in with all my might.
8To brag or talk big — to exaggerate one's own abilities or achievements (colloquial usage).
彼は昨日の勝利について大げさに吹いていた。
He was bragging exaggeratedly about yesterday's victory.
実力以上に吹くのはやめたほうがいい。
You'd better stop talking yourself up beyond your real ability.
9To smelt metal, or to cast molten metal into coins — an old or technical usage.
かつてこの地域では銀を吹いて貨幣を作っていた。
In the past, this region used to smelt silver to mint coins.