tōng​xiǎo

to be proficient in

通晓 通曉 tōng​xiǎo
to be proficient in
to understand something through and through; to be well-versed in or have a thorough command of a subject or skill
throughout the night
(literary) lasting from evening until dawn; all night long

Frequency

Movie subtitles
1.34 per million appears in 0% of films
Written text
0.883 per million

Sources