I love love love [name]Thomasina[/name]! After [name]Phillipa[/name], it’s my favorite feminine version of a classic boy’s name.
I want to love [name]Tamsin[/name] but for some reason don’t. I think I too would also worry too much about the nickname [name]Tammy[/name].
I think the nickname [name]Tommy[/name] or [name]Tommi[/name] would be much cuter from [name]Thomasina[/name].
I don’t know – somehow I think [name]Tamsin[/name] lacks a bit of seriousness and heft. I want her to be a surgeon. Kidding! (kind of).
[name]Tammy[/name] as a nickname keeps me up at night! I hear you!
I like [name]Thomasina[/name] but I don’t see how [name]Tamsin[/name] is a nickname of that. And as previous posters said, [name]Tamsin[/name] is a mouthful for a nickname. To me nicknames are short and sweet. I really don’t care for [name]Tamsin[/name]. I think a better nickname for [name]Thomasina[/name] would be [name]Tommie[/name]. Or if you were to use [name]Tamsin[/name] then I like the nickname [name]Tammy[/name].
I am going with definitely Fabulous!
I’m not a huge fan of either name BUT I love the creativity of the nickname! I say go for it. 
It’s not a “random nickname” : [name]Tamsin[/name] is a legitimate nickname for the Cornish name [name]Thomasina[/name] and has been for hundreds of years. sigh!
fabulous!
I had no idea that there was a cat called [name]Thomasina[/name], but I’ve got a cat called [name]Tamsin[/name], lol (not that I think of it as exclusively a cats name). Despite our mutual distaste for it, we tend to call her [name]Tammy[/name], so I would say that if you are going with either name, you want a nn that is ready to go before that can happen (I’ve recently tried to start a movement towards Tams or Tamsy, which is more tolerable to me). [name]Tamsin[/name] as a nn for [name]Thomasina[/name] does feel a bit forced, even though it is legitimate. I loved the suggestion of [name]Maisie[/name] as a nn for [name]Thomasina[/name].
Whatever you decide, though, I think they’re both beautiful, distinctive names.
I think it is fabulous and ready for a comeback! My grandfather was Thomas and I have always thougt of putting Thomasina and or tamsin on my list. It’s a brave choice, but cutting edge I feel, bringing back fusty feminizations that haven’t been overused or become trendy again, I put Eugenia, Henrietta and Augusta in this camp as well.
The thing is though, with sister Lara, Thomasina seems to be a whole lot of name, comparatively heavier, while Lara seems sleeker and more modern. Spunky Tamsin on it’s own, however, with Lara I think is great! You know she would be the only one in the sandbox! Also I could see Tamsin being a surgeon or a painter. It’s so distinctive, I see it as similar to Tess and Tanith/Tanis. I love the suggestion of Maisie as a nn in order to avoid the dreaded Tammy.
I [name]LOVE[/name] [name]Thomasina[/name]! It’s feminine and formal. Classic, yet fresh. I never would have thought of it on my own–and thats my favorite part. I’ve never met a [name]Thomasina[/name] before, but I know exactly how to pronounce it. That’s a sure fire recipe for a great name.
[name]Tamsin[/name], though, I just don’t love so much. I knew a [name]Tamsin[/name] in high school and she was really nice and trendy and fun. But to be honest, I always thought she had an ugly name and that it didn’t suit her. I get that this is a classic nn for [name]Thomasina[/name] and that you love it and that is, of course, the most important thing! [name]Will[/name] people want to call her [name]Tommie[/name] (or something similar)? Probably not if you always call her [name]Tamsin[/name].
That said, I usually want a girl’s nickname to be at least one or two of the following things: flirty, tomboyish, fun, light, easy to yell on the playground, easy for a little one to pronounce. Personally, I think the nickname that hits all these points (but tomboyish) is [name]Maisie[/name]. What a fun, light nickname for a formal beautiful name! I love that it shares some vintage charm with [name]Thomasina[/name]. Are you interested in it at all?
I love [name]Tamsin[/name], and I like [name]Thomasina[/name]. I think [name]Maisie[/name] is truly awful, though.
Gah!!! You make an excellent argument. We’re onto ‘[name]Adrianne[/name]’ now… decisions, decisions.