This may seem silly, but [name_m]Kier[/name_m]/[name_m]Keir[/name_m]/[name_u]Kieran[/name_u] mean dark haired and my little boy (due in [name_u]December[/name_u]!) will likely be very fair with blond hair (me, my husband, and daughter all are blond, blue eyed as well as many other family members). Would that deter you if the name meaning was specific to a certain look that the child likely won’t have or is that really overthinking it if we like the name? Thanks!
I wouldn’t worry about it, because the meaning is not at all obvious. You’d have to look it up, and technically I think it just means ‘black’, not necessarily ‘dark-haired’. I think ‘[name_u]Raven[/name_u]’ would be kind of funny on a blonde kid, but [name_m]Kier[/name_m]? Not a problem. I know a child named something which literally means ‘coal-brow’, i.e ‘black-haired’ and the meaning is obvious in the local language, and she’s blonde. Now that I find a bit silly, but even that isn’t really an issue. It’s just her name.
Isn’t keir also a derogatory word for penis in Farsi…?
I think it’s fine. Very few people would know [name_m]Keir[/name_m]/[name_m]Kier[/name_m]/[name_u]Kieran[/name_u] means dark haired. I’d gladly name my daughter [name_f]Flavia[/name_f] (golden/blonde), even though it’s very unlikely I’ll ever have a daughter with blonde hair. I know someone called [name_m]Kier[/name_m] (although he does have dark hair), but I wouldn’t think anything of it if he was blond.
It’s fine. Most people don’t know the meaning of names, and if they look them up, they forget soon enough.
It means dark. That doesn’t mean dark haired. I think that is suitable for a baby born in [name_u]December[/name_u] because [name_u]Winter[/name_u] is dark. Or perhaps, a baby born at night?
I think it’s fine. As others have said, most people don’t know the meaning of names, so I doubt anyone would question it. I quite like the name [name_m]Kier[/name_m]/[name_u]Kieran[/name_u].
I don’t think it’s a problem. Most people don’t even know the meanings of their own names. I prefer [name_m]Keir[/name_m] to [name_m]Kier[/name_m].
I have known several boys named [name_u]Kieran[/name_u] who were blonde. I have ony met one [name_m]Keir[/name_m] - he was dark haired, but I wouldn’t have batted an eyelid if he was blonde (dark hair suited him though, he was a hottie!) [name_m]Keir[/name_m] and [name_u]Kieran[/name_u] are more popular here in the UK so if you’re in the US, I would worry even less because most peole will not know the name.
I wouldn’t think it was odd in the least. I prefer [name_m]Keir[/name_m] to [name_m]Kier[/name_m], but for more authenticity, I love [name_m]Ciar[/name_m]!
I wouldn’t worry about it, it doesn’t mean dark haired… While I do think it important to have a name that suits a child I think you’re quite safe there and even if it meant that would be. If you love the name and you can see the name on your child. If you’re saying it bothers you to a degree because you feel the name is painting a picture that you think won’t be the case then perhaps a light middle name 
whatever makes it feel natural and comfortable to you.
[name_f]My[/name_f] nephew is a blond [name_m]Kier[/name_m]. I think it’s fine. Dark could mean mercurial, serious, born in the dark month of [name_u]January[/name_u] (as he was).
[name_f]My[/name_f] larger concern with the name is the spelling; I personally feel that [name_m]Keir[/name_m] looks misspelled because of the whole “I before E except after C” rule of the English language.