Webster's Revised Unabridged Dictionary · 1913

Kotow

Kotow , noun

[Chinese, knock head.]

Same as kowtow, the more common spellings. [China] — S. W. Williams

Kotow , intransitive verb

1.
To perform the kotow. Now usually spelled kowtow.
2.
To defer to another in a servile or humiliating manner; to act obsequiously.