Quenya name help?

Mae govannen! Again I'm here to seek for help with a Quenya name translation. The English meaning I came up with is "evanascent lament". Yet obviously there isn't a Quenya word matching "evanascent" specifically; neither am I certain about the appropriate synonym. I wish someone could help me find a suitable word. As for "lament", I've got "nainië/nairë/siquilë" and isn't sure about their differences, thus I can't make a choice among them. Therefore, I'm really looking forward to your help and suggestion. Many thanks in advance!?

Merriam-Webster gives synonyms of evanescent as

brief, deciduous, ephemeral, flash, fleeting, fugacious, fugitive, impermanent, momentary, passing, short-lived, temporary, transient, transitory

xiéte is a Quenya adjective meaning "passing, impermanent".

nainie is fine for "lament"

Thanks a lot! That's such an amazing site. I believe it'll even help me with English learning and writing in the future.?

With the counsel of the synonyms, I got "senwa" in place of "xiétë" for "moment, instant", since the former seems easier to put in and be pronounced in a name. (The problem is that "senwa" is a fan-invented noun. Does that matter?)

Thus the combination appears to be "Nairesenwa[=naire(n. lament)+senwa(n. moment, instant)]". This is the shortest one to be created within my (poor) ability. I'd still appreciate comment and suggestion on whether the order of the two words is right\ whether it's appropriate as a female name, etc..

Many thanks again for your help!

Well, senwa was actually my invention; I have coined it from the adjective senna "short", and that may suit you better.

In Quenya compounds and compound names the adjectives, as a rule, precede the nouns, so senna would come first and then naire. But this results in *sennanaire, and the double na in the middle would probably simplify, yielding *sennaire. And for it to be a well-formed name you also need a feminine suffix: Sennairiel "short lament".

How does that sound?

That sounds nice! It also looks well in Tengwar. I think I'm going to take that directly. Thanks so much for helping and teaching me the rules!☺️