晦氣晦氣 What Rotten Luck Today
急伸頭摸摸，把頂梁皮都撞軟了。自家心焦道：「晦氣，晦氣，這顆頭今日也不濟了。常時刀砍斧剁，莫能傷損，卻怎麼被這金光撞軟了皮肉？急伸头摸摸，把顶梁皮都撞软了。自家心焦道：「晦气，晦气，这颗头今日也不济了。常时刀砍斧剁，莫能伤损，却怎么被这金光撞软了皮肉？
逐句解 Line by line
He put a hand up quickly and felt about, and found he had knocked the skin on the crown of his head soft.
頂梁 carries 梁, roof-beam — the same character that named the 屋梁 the poison box was hidden on — and here it means the crown of the skull, the ridge-pole of a person. 撞軟, knocked soft, is a horrible little compound: not cut, not broken, softened.
Fretting to himself, he said, "Rotten luck! Rotten luck! This head of mine is no good at all today."
晦氣 is bad luck, an ill-omened day — literally darkened air — and it is still exactly what a Chinese speaker mutters when things go wrong. Doubled, as this chapter doubles everything said with feeling. 不濟 means not up to it, no use, and 這顆頭 counts the head with 顆, the measure word for small round things: pearls, teeth, hearts.
"Ordinarily sword-cuts and axe-blows could do me no injury. How is it this golden light has knocked my skin and flesh soft?"
刀砍斧剁 — hacked with knives, chopped with axes — is a four-character boast of invulnerability, and it is true: Pilgrim's body was tempered in Lord Lao Zi's furnace and blades do not mark it. The question he is asking is a real one and the chapter never answers it.
This is the funniest thing in the chapter and it is entirely at the hero's expense. The Great Sage Equal to Heaven, invulnerable to blades, sits in the dirt feeling the top of his own head and complaining about his luck. 晦氣，晦氣 is the register of a man who has stubbed his toe.
The comedy works because the physical detail is exact. He does not say he is wounded; he says the skin on his crown has gone soft, which is what a bad bump actually feels like under the fingers. Anyone who has walked into a low doorframe has performed this exact gesture.
And underneath it there is a genuine puzzle. Swords cannot mark him. This light has. Whatever the thousand eyes are producing, it is not a physical force in the ordinary sense, which is why the cudgel has been no use for the last two passages and why the solution, when it comes, is not to fight at all.