I use Renshuu for learning Japanese idioms. Often they have similar meanings, but (possibly due to lack of demand) these are not considered so, so I often get marked wrong.
I guess maybe we can have an option to mark a term as "similar", so that when we use it next time, the system gives "there is another correct answer" to try again, instead of directly marking as wrong
You can also customize the definition in the dictionary to be more specific. For instance, I would consider redefining 火を見たら火事と思え(ひをみたらかじとおもえ) to something like “only you can prevent forest fires.”
