We've all had this experience: You hear a new word (say, skoosh or spim), kinda-sorta think you know what it means, but then forget it nearly as soon as you've heard it. Why can't you make that newly learned word "stick"? Probably because you never really learned it.
Knowing how to use a word is just as important as knowing its meaning. And we tend to remember words more easily when we read about them in meaningful context, when we see that they are useful and worth remembering, and also when they have been fully explained.
A new word is not just "dumped" into your brain. Learning it is part of a great process in which the brain creates neural connections between the new word and others in your mental lexicon. This helps you develop new perceptions and concepts, which increase the chances of your remembering the new word. The more information you get about a word, the more likely you will remember it and use it in its proper context.
All dictionaries offer example sentences to a degree, and there are websites like Oxford Dictionaries that offer huge databases of example sentences. Among other English dictionaries, print and online, you will find that learners' dictionaries, contain the highest number of examples. A number of them offer free online lookups: Cambridge Advanced Learner's Dictionary, Oxford Advanced Learner's Dictionary, and Merriam-Webster's Learners Dictionary.
How else can you make a new word "stick"? Use a dictionary's etymology (word history), the other definitions for the word, the derivatives of the word, and even synonyms and cross-references. The more you think about and understand a word, and the more information you process about it, the more likely it will "stick."
Still struggling? Try mind mapping, which is essentially a word association exercise on paper. Take your word-of-the-day and start connecting it to other related words. If your new word is gaucherie, you can connect various words to it, such as tactless, boorish, awkward, faux pas, gaffe, blunder, unsophisticated, embarrassing, gauche manners, etc. Instead of just reading or hearing your new word and going on to your next activity, you have taken a few minutes to make notes that will help your brain set up neural interconnections. You could even add your own example of how you might use the word as one of the mind map threads.
Remember, to learn how to really use a specific word, don't rely on just one of the strategies given above. Use several techniques. Try them all out and see which ones work best for you. Learning really is more effective if it is fun, so use the techniques you enjoy.