維基辭典YuePhrase
Original phonetic: /sœːŋ⁵⁵ faːn³⁵ sœːŋ⁵⁵ sɪŋ²¹/
to be both opposite and complementary; to oppose each other and yet also complement each other
Examples
怎樣解釋戰爭中提倡勇敢犧牲呢？豈非與「保存自己」相矛盾？不相矛盾，是相反相成的。
How do we justify the encouragement of heroic sacrifice in war? Does it not contradict "self-preservation"? No, it does not; sacrifice and self-preservation are both opposite and complementary to each other.