Calum. It sounds far calmer and more delicate than the rough
Conor. I prefer the meaning of
Conor, though.
Connor and
Callum are how I'd instinctively spell both names, but I think people would be more likely to get
Conor correctly.
Callum is definitely a two syllable name to me - I'm half English.
masculine list:
https://www.behindthename.com/pnl/191050/124079feminine list:
https://www.behindthename.com/pnl/191050/124080