天馬行空 [ㄊㄧㄢ ㄇㄚˇ ㄒㄧㄥˊ ㄎㄨㄥ; tian1 ma3 xing2 kong1] like a heavenly steed, soaring across the skies (idiom) (of writing, calligraphy etc) bold and imaginative unconstrained in style ◄ ►