I am not sure I like gwedh "bond" for articles of clothing. It feels off.

There is G. brach "shawl, plaid, wrap" and G. braitha- "wrap, swathe". These could have developed from a triconsonantal root BARAK, from primitive *b'rakke and *b'rakta-, though in Sindarin phonology the verb would become S. braetha-.

Maybe lang "throat" + brach "wrap" > lambrach > lamrach "scarf".

iaethwedh "neck-bond" sounds suitably painful for a necktie, though, in the unlikely event you could convince an Elf to wear one :)

Good point!

Gnomish had brach "a shawl, plaid, wrap". Or perhaps against "neck-wreath/wrap" (goe, *gwae–f/–dil for Qe./Q vaima, *–(n)cë ?) consider the pattern "neck-veil/cover", after the use of rica, ricula in Contemporary Latin.

Something like *langwaef? Anyway brach sounds quite like other S words, and for simplicity I will consider using that instead.

Or simply *gwaef.