Transferred use of surname that started out as a boy's name, but is currently more common for girls. Originally an English form of the ancient Irish Gaelic name Ceallach, that debuted on the chart in 1944 and rose to a strong position among the top 100 in 1959. Peaked at No. 10 in 1977, because of fictional character, "Kelly Garrett," played by actress Jaclyn Smith on the 1976 to 1981 television series, "Charlie's Angels." Singer Kelly Clarkson, the 2002 first season winner of "American Idol" also comes to mind. Trendy name with a "y" spelling and long "ee" sound either by itself or combined with other names like Kellyjo or Kelly-Ann. , Lively: aggressive.