Short or courtier
A modern phonetic spelling of Courtney. It originates from an Old French surname, 'curt' meaning short and 'nez' meaning nose, or alternatively referring to someone who lived at a court.
Less common today
Kortnie isn't in the latest US Top 1000. It last peaked at #2,264 in 1993.
US births per 5-year period, 1990βpresent (SSA data).