龍王變士 The Dragon King Takes a Scholar's Form
龍王依奏，遂棄寶劍，也不興雲雨，出岸上，搖身一變，變作一個白衣秀士，真個：龙王依奏，遂弃宝剑，也不兴云雨，出岸上，摇身一变，变作一个白衣秀士，真个：
逐句解 Line by line
The Dragon King, heeding their counsel, laid aside his precious sword, raised neither cloud nor rain, came up onto the bank, gave his body a shake, and changed himself into a scholar robed in white — truly:
依奏 is 'to act on the petition'; 興 in 不興雲雨 ('to raise neither cloud nor rain') is xīng, 'to stir up.' 搖身一變 ('one shake of the body and a transformation') is the stock formula for a shape-shift, and 白衣秀士 a white-robed licentiate; 一 is yí before the falling tone of 變. The 賦 that follows describes the disguise.
His bearing noble and imposing, he seemed to tower over ravines and rise to the very sky.
丰姿英偉 is 'a fine and heroic bearing'; 聳壑昂霄 ('rising over gorges, lifting to the clouds') is a set phrase for a commanding presence.
His gait was measured and dignified, and in all things he kept to compass and rule.
端祥 (= 端詳) is 'grave and composed'; 循規蹈矩 ('to follow the compasses and tread the square') means to observe every propriety.
In speech he followed Confucius and Mencius; in manner he embodied the decorum of the Duke of Zhou.
孔孟 are Confucius and Mencius; 周文 evokes the civilizing rites of the Duke of Zhou and King Wen. The couplet paints the very picture of a Confucian gentleman — the dragon's chosen disguise.
He wore a gown of jade-colored gauze with a bordered hem, and on his head a carefree scholar's flat kerchief.
羅襴服 is a gauze robe with a horizontal border at the hem (襴, lán), formal scholar's dress; 逍遙一字巾 ('a free-and-easy one-bar kerchief') is a soft head-cloth folded in a straight band. 一 is yí before 字.
Persuaded by his ministers, the Dragon King sets aside sword and storm and goes up into the world of men disguised as a Confucian scholar — 搖身一變, 'one shake of the body,' the novel's standard formula for transformation. The 賦 that renders his appearance is pure Confucian portraiture: a noble bearing, a measured gait, speech modeled on Confucius and Mencius, manners after the Duke of Zhou, and the gauze robe and flat kerchief of a licentiate.
There is a quiet irony in the costume. The dragon — a creature of appetite and wrath, about to gamble his life out of wounded pride — cloaks himself in the very image of self-restraint and propriety, 循規蹈矩, 'keeping to compass and rule.' The disguise he chooses is precisely the virtue he lacks, and the gap between the borrowed decorum and the rashness beneath it is the seed of everything that follows.