Among Mark Twain's rules for writers is this one: Use the right word, not its second cousin. Great advice. Unless the right word does not exist in the English language.
I encounter this problem a couple of times in every story. I can think of several second cousins to the word I need but not the one word that communicates the perfect tone or mood. I comb the thesaurus in search of that perfect word but cannot find it. Eventually, I either go with a second cousin or write around the problem.
One that turns up occasionally: a substitute pronoun for whose that can be used in conjunction with inanimate objects. Who is used when talking about a person, that and which when talking about an inanimate object. But whose has no equivalent for use with non-human nouns. Example: "A country whose GDP is increasing." Not a good example, because I can think of plenty of ways to write around that one, but you get the idea.
In my current work in progress, the word that is giving me fits is kidnap. This is a fine word, if the person who is taken is a kid. Alas, the victim in my story is an adult, and "kidnap" sounds wrong to my writerly ear. OK, you say, so use abduct. Again, to my mind, this is not quite right. Anything can be abducted if it's carried off by force, while only a person (or maybe a pet) can be kidnapped.
Now you're saying to yourself that I'm over-thinking the whole thing, and you're probably right. But that's what comes of working as a copy editor for 40 hours per week for 10 years. I get obsessive about words.