'kowtow' originates from the Chinese word '叩头' (kòu tóu), where '叩' meant 'to knock' and '头' meant 'head.'

'叩头' transformed into the English word 'kowtow' through transliteration.

Initially, it meant 'to knock one's head on the ground as a sign of respect,' but over time it evolved into its current meaning of 'to act in an excessively subservient manner.'