If someone can come up with a functional reverse dictionary, I think they could make a great deal of money on the ads they would no doubt coat their webpage with, since that’s how it’s done these days.
For example, take a word like homunculus. Say you want a similar word, but with a non-person meaning. (If it were a math equation imagine Homunculus – person + thing) As in a perfectly formed tiny version of a thing. Maybe it’d give you simulacrum or something similar as a result, even though it doesn’t quite match the parameters.
My point being that English has a metric stuffload of words and it’d be nice if it came with a manual to navigate from word to word so you could fall back upon it when your mental reference materials inevitably came up short.