The Collaborative International Dictionary of English v.0.48:
Kotow \Ko*tow"\, v. i. [imp. & p. p. Kotowed; p. pr. & vb. n. Kotowing.] 1. To perform the kotow. Now usually spelled kowtow. [Also spelled kowtow.] [1913 Webster] 2. To defer to another in a servile or humiliating manner; to act obsequiously. [PJC]