mum and umm tie for the highest Scrabble score from mum at 7 points. The top 5 of 5 words are shown here, with the full list organized by length below.
There are 2 three-letter words hiding in mum: one comes from rearranging its letters, and mum itself is already a playable word with no unscrambling required. No common everyday answer stands out among these three-letter results, so let the score decide: the highest-scoring words are mum and umm, each worth 7 points in Scrabble.
Swap a single tile in mum and you get a different three-letter rack with its own word list. None of these appear in the results above — they share 2 of the 3 letters, not all of them.
mum 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 3-point gap between the two totals comes from the tile values themselves: Scrabble and Words With Friends price the same letters differently.
Dictionaries record four senses for mum. Scrabble and Words With Friends score tiles and not meanings, so every sense below is worth the same 7 points on a Scrabble board:
mum is one of two three-letter words the same letters produce. No arrangement of the same tiles scores higher in Scrabble, so playing mum unchanged also takes the maximum points these letters offer.
The highest-scoring plays from these letters are mum and umm, worth 7 points in Scrabble, and nothing else built from mum 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 mum produce 5 valid words in the Scrabble and Words With Friends dictionaries. The word count by length is: 2 three-letter words and 3 two-letter words.