渙然冰釋

From the Tao Te Ching, Chapter 15:

儼兮其若客，涣兮若冰之將釋，敦兮其若樸，曠兮其若谷，混兮其若濁。 [Classical Chinese, trad.]
俨兮其若客，涣兮若冰之将释，敦兮其若朴，旷兮其若谷，混兮其若浊。 [Classical Chinese, simp.]

From: Tao Te Ching, 4^th century BCE, translated based on James Legge's version

Yǎn xī qí ruò kè, huàn xī ruò bīng zhī jiāng shì, dūn xī qí ruò pǔ, kuàng xī qí ruò gǔ, hùn xī qí ruò zhuó. [Pinyin]

Grave like a guest (in awe of his host); evanescent like ice melting away; unpretentious like wood that has not been fashioned into anything; vacant like a valley, and dull like muddy water.

渙然冰釋

1. (figurative) to melt away; to thaw out; to clear up; to vanish to the four winds