I recommend using dedicated sites rather than simply typing into the search engine of your choice, or checking out a wiki. Both are good, but the professional lexicographers and their sites offer far more than just giving you a meaning. My preferred two are: Oxford Dictionaries and Collins Dictionaries.
OK, most provide thesauruses, grammar tips and some translation and these do too. However, I have found nice little extras.
Oxford Dictionaries has sections on quotes, phase meanings, word origins, I find myself exploring the site for ages after the original word meaning has been fully understood and probably forgotten. Hey, I used - OK, I still do - word surf paper dictionaries, it's a weakness.
So what about my title to this blog? I discovered on the Collins's site a 'Word Usage Trend' indicator for every word you look up (it's near the bottom of the page). It shows the trend over 10 years; however, there is a pull down so you can look at the frequency of use over 300 years. Tenderness, the word, peaked in frequency around 1828 then has been on a gradual slide ever since. If you put in 'impatience' you'll see it peaks a little earlier then declines.
Is this a laziness in word usage? I don't know. Have there been new, better words superseding old ones? Maybe. I don't know the reason, I do know that over 300 years there have been a lot more words created and a lot more things written, much thanks to the Internet, which might dilute frequency of word usage. It doesn't really matter its just a cool feature. When you next look up a meaning or spelling, check out how it is trending, not over the last five seconds on Twitter, but over three centuries.
By the way, I then tried to think of a word where its usage was rising, my best so far was 'mobile' for obvious reasons.