胼手胝足 [－－－－]

Jyutping pin4 sau2 zi1 zuk1
Pinyin pián shǒu zhī zú

Definitions (CC-CEDICT)
  1. lit. with calluses on hands and feet (idiom)
  2. fig. to work one's fingers to the bone
Definitions (Wiktionary)
  1. phrase, idiomatic
    long toiling