孜孜(しし)

diligently; industriously

孜々(しし)として

diligently; assiduously

孜々営々(ししえいえい)

working diligently and continuously

孜々不倦(ししふけん)

tirelessly diligent

孜々汲々(ししきゅうきゅう)

diligently and painstakingly

孜々矻々(ししこつこつ)

diligently and tirelessly

孜々勉励(ししべんれい)

working diligently and studying hard

孜々不怠(ししふたい)

diligent and unremitting

彼(かれ)は孜々(しし)と励(はげ)む姿勢(しせい)を崩(くず)さない。

He never abandons his industrious attitude.

研究者(けんきゅうしゃ)は孜々不倦(ししふけん)の努力(どりょく)を重(かさ)ねた。

The researcher made tireless efforts.