
ZA
Definition:
: pizza (plural: ZAS)
About the Word:
ZA (often found in print as 'za) is a slang shortening of the word pizza. You may be surprised at some of the slang words found on the tournament SCRABBLE board: BRO, HOMEY, and YO are all accepted.
ZA is the most played word containing the letter Z (and the only playable two-letter word with the letter Z) in tournament SCRABBLE play.
Incidentally, .za is the country code for South Africa (Zuid-Afrika is Dutch for "South Africa"), but abbreviations and codes are not acceptable on the SCRABBLE board.

QI
Definition:
: the vital force that in Chinese thought is inherent in all things (plural: QIS)
About the Word:
Devoted SCRABBLE players use the dictionary as their arsenal. Every variation of a word - plural forms, alternate spellings - can be used to gain the edge in competition.
Although it's most commonly spelled CHI in standard usage, the variant form QI is the single most-played word in SCRABBLE tournaments, according to game records of the North American SCRABBLE Players Association (NASPA).

PHONEY
About the Word:
You probably associate bluffing with poker, but it is just as much a part of serious SCRABBLE play. Tournament players will often make up words that look legitimate to the untrained eye - fake compounds like OUTMANAGE, or plausible misspellings like EJECTER.
The choice to play a phoney is a strategic one. (And note: the spelling of the SCRABBLE-specific noun is not the usual phony.) If your opponent doesn't challenge you, your bluff can earn you points and strengthen your position. If you lose a challenge, you lose your turn.
"People win games by taking advantage of their opponents' mistakes. Knowing the idiosyncrasies of our language is a huge advantage over those who do not," says SCRABBLE champ Chris Cree.

RETINAS
Definition:
: plural of RETINA, a membrane of the eye
About the Word:
Getting a rack with these seven letters can be viewed as a SCRABBLE bulls-eye. RETINAS has eight accepted anagrams - ANESTRI, ANTSIER, NASTIER, RATINES, RETAINS, RETSINA, STAINER, and STEARIN - which means nine different words can be played using those same seven letters.
The strategic player will evaluate which anagram scores the most, which might most likely be challenged, and which might best accomplish the player's desired board strategy.

XU
Definition:
: a monetary unit of Vietnam (plural: XU)
About the Word:
X is a very powerful tile: all five vowels work with the eight-point X to make two-letter words (AX, EX, XI, OX are the four other words). When the X tile is used in an overlapped two-letter play with the X on a triple letter score, the player will almost always score at least 52 points.

ZLOTY
Definition:
: a monetary unit of Poland (plural: ZLOTYS)
About the Word:
Most foreign currencies, like the previously mentioned XU, plus COLON (plural: COLONES), FRANC, KORUN (plural: KORUNAS, KORUNY, or KORUN), PESETA, NAKFA) are acceptable words. ZLOTY is powerful both because it has the valuable ten-point Z and because it has the unusual -YS plural.