My lineart is kinda medium-thin, but with variation in line weight, tapered points, and a smooth flow. I use long sweeps of the pen as much as possible. I take it a little chunkier on occasion, for cuter, simpler illustrations.
It's quite funny, for many years I hated doing lineart. It's always been my least favourite part of my illustration process. I've tried a number of times to ditch it entirely, or at least make it messy enough to blend more organically with a looser illustrative painting style, but what I want and what I'm good at are two very different things. And, as it turns out, over my many years of making art, I've somehow magically become really good at clean lineart, despite never intending for that to happen. At all.
It's kinda ridiculous to have the part of your style you like the least be one of the parts which is complimented the most, and to know deep down that it is actually one of your bigger artistic strengths, but still wish it looked totally different.
I'm finally starting to embrace it now. Especially as it's clicked with me that the definition and clarity of my lineart is ideal for the style of TV-animation-esque comics I want to make. I'm really loving the way it looks in my comic, and it's a very fashionable style for graphic novels at the moment, so while 'fashionable' was never my intention - hooray for happy accidents!