OneLook Reverse Dictionary
www.onelook.com/reverse-dictionary.shtml
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
OneLook's reverse dictionary lets you describe a concept and get back a list of words and phrases related to that concept. Your description can be a few words, a sentence, a question, or even just a single word. Just type it into the box above and hit the "Find words" button. Keep it short to get the best results. In most cases you'll get back a list of related terms with the best matches shown first.