yirr needs no unscrambling at all — the four-letter word is already the strongest play its own letters allow, banking 7 points in Scrabble as it stands. In all, 1 valid word comes out of this rack, grouped by length below and checked for Words With Friends as well as Scrabble.
yirr is the highest-scoring word from yirr, worth 7 points in Scrabble. The top 1 of 1 word is shown here, with the full list organized by length below.
Only one four-letter word uses the letters in yirr — and it is yirr itself. No unscrambling is needed: the word is already playable as written, worth 7 points in Scrabble.
Swap a single tile in yirr and you get a different four-letter rack with its own word list. None of these appear in the results above — they share 3 of the 4 letters, not all of them.
yirr is in the NWL, the official Scrabble word list for North America, and in the Words With Friends dictionary, so it's playable exactly as it stands and needs no unscrambling.
The 1-point gap between the two totals comes from the tile values themselves: Scrabble and Words With Friends price the same letters differently.
yirr is the only four-letter word the same letters produce. No arrangement of the same tiles scores higher in Scrabble, so playing yirr unchanged also takes the maximum points these letters offer.
The highest-scoring play from these letters is yirr, worth 7 points in Scrabble, and no other word from yirr earns more points in Scrabble. Words With Friends prices the same letters differently, so the top of the list changes on a Words With Friends board. Both scores count tile values only and exclude premium squares.
The letters in yirr produce 1 valid words in the Scrabble and Words With Friends dictionaries. The word count by length is: 1 four-letter word.