火本身
這就是核心畫面本人，其他三支都可以想成從這裡延伸出去。
noun · B2
A sudden short burst of flame, especially when fat or oil drips onto a hot grill and the fire jumps up for a moment.
火焰突然竄起
核心畫面
A good way to hold this word: picture a fire that is already burning steadily. Fat drips on it, and for a second or two the flame leaps up — then it drops back to where it was. Everything flare-up is used for keeps that shape. Something was quiet, something jumps, and the jump is understood as one stretch rather than a new permanent state. That is why English counts them — one or two flare-ups — and why the calm before and after is always part of the picture.
可以想成一團本來燒得穩穩的火。油滴下去，火竄高一兩秒，然後又降回原來的高度。flare-up 所有的用法都留著這個形…更多收起
可以想成一團本來燒得穩穩的火。油滴下去，火竄高一兩秒，然後又降回原來的高度。flare-up 所有的用法都留著這個形狀。本來是安靜的。忽然衝起來一下。而且大家理解成「一陣子」，不是從此變成新的常態。這就是為什麼英文會把它一次一次地數（one or two flare-ups），也是為什麼前後的平靜總是畫面的一部分。抓住這個畫面，脾氣、病痛、數字三種用法就不用分開背。From the word’s history
Wiktionary records flare-up as deverbal from the phrasal verb flare up, and notes the word was originally used of flame and only later of any violent activity or emotion.
Wiktionary 記錄 flare-up 是從動詞片語 flare up 直接變成的名詞，而且註明它原本講的是火焰，後來才擴大到各種激烈的活動或情緒。所以把火的畫面放在最前面，不是我們編出來的比喻，而是這個字自己走過的路。
Wiktionary entry for flare-up (kaikki:3f6f69a190036ae4:1443425983:8646): "Deverbal from flare up"; sense 0 gloss "originally of flame, but now used more generally of any violent activity or emotion".
Four branches
人的火氣
把火換成脾氣：本來相安無事，忽然聲音大起來，然後又平息。
noun · B2
A short, sudden burst of anger or fighting between people who were calm a moment before, and who usually calm down again afterwards.
突然發火／突然起衝突
身體裡的火
把火換成身上壓著的老毛病：它一直在，只是這陣子又燒起來。
noun · B2
A time when an illness or an injury you have had for a long while suddenly gets worse again, after a quiet period when it was giving you little or no trouble.
（舊病）突然發作／復發
數字和情勢的火
同樣的竄高畫面，只是這次竄起來的是數量或情勢。
noun · C1
A sudden sharp rise in some activity after a quiet period — for example in fighting between two sides, in the number of people falling ill, or in demand for something.
（活動、情勢）突然升高