There are roughly 173,000 words in the Words With Friends® dictionary. Unless you plan to forsake your family, your friends, and your life, there is very little chance of you memorizing them. Even if you assume that a third of these words are over 10 letters, and would never appear in a normal game, you still are faced with a daunting task.
However, some of these words are much more important to know than others. Let's take two hypotheticals to demonstrate this. Let's say that you have the letters AEINORT in your rack. There is no 7-letter word these can make, but there are ten 6-letter words. If you didn't know about AROINT or NORITE, you would still be fine if you knew the more common words like ORIENT, ORNATE, RATION, RETAIN, or RETINA. In other words, it's not a disaster in this situation if you don't know the word AROINT.
However, let's say that you have the letters ADINQRZ in your rack. In this case, there is only one 6-letter word you can make -- QINDAR. Furthermore, there are only a handful of 5-letter words, and none of of those use the Q or Z. In this scenario, you could miss out on a lot of value by not knowing the word QINDAR.
One metric that has been developed to measure this value is O’Laughlin playability. In short, QINDAR would have a much higher O’Laughlin playability than AROINT, because the consequences of not knowing QINDAR are likely to be more severe if the situation comes up in a game. The metric was computed by John O’Laughlin, using Quackle (per this site).
Another dimension of this metric is the likelihood of drawing the letters on question. There are hundreds of letter combinations which can only make a single 7-letter or 8-letter word. However, ERASION, for instance, is ranked the highest because you are much more likely to draw these tiles than, for instance, ZAMBUCK.
We have a tool on this site to help you memorize these words. But for now, to give a general idea, here are the ten Words With Friends® words with the highest O’Laughlin playability for a given number of letters. Learning this list alone will be immensely helpful. Of particlar importance are the 2 and 3-letter words within this set.
XI, OX, QI, ZA, EX, AX, JO, XU, OF, IF
QAT, QIS, QUA, JOE, ZEE, OXO, AXE, SUQ, JEE, VEX
QADI, QAID, QATS, JIAO, ZOEA, QUAI, QUOD, IXIA, AJEE, JIVE
TRANQ, QANAT, FAQIR, ZOEAE, QUEEN, QUOTE, AQUAE, NERTZ, ZAIRE, ZOWIE
QINTAR, QINDAR, QIVIUT, FEIJOA, EQUATE, QUIVER, ZOUAVE, QUINOA, QUAERE, QUAVER
ERASION, ETESIAN, ATONIES, INERTIA, TAENIAE, SERIATE, INOSITE, ROSEATE, SENARII, ANISOLE
AERATION, INERTIAE, AEROLITE, ANTERIOR, INERTIAL, DETAINEE, DAINTIER, ERADIATE, TENORITE, ETIOLATE
The words in our dictionary are meant to match, as closely as possible, the words used in Words With Friends®. We have no affiliation with Words With Friends, and offer this site for entertainment purposes only.