Son of Kenneth; fair one
A modern American creative spelling of the Scottish surname Mackenzie. It derives from the Gaelic 'Mac Coinnich', meaning 'son of Coinneach', which translates to 'fair one' or 'handsome'.
Less common today
Mckynzee isn't in the latest US Top 1000. It last peaked at #12,009 in 2012.
US births per 5-year period, 1990βpresent (SSA data).