op and po tie for the highest Scrabble score from op at 4 points. The top 2 of 2 words are shown here, with the full list organized by length below.
There are 2 two-letter words hiding in op: one comes from rearranging its letters, and op itself is already a playable word with no unscrambling required. No common everyday answer stands out among these two-letter results, so let the score decide: the highest-scoring words are op and po, each worth 4 points in Scrabble.
op 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.
op is one of two two-letter words the same letters produce. No arrangement of the same tiles scores higher in Scrabble, so playing op unchanged also takes the maximum points these letters offer.
The highest-scoring plays from these letters are op and po, worth 4 points in Scrabble, and nothing else built from op 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 op produce 2 valid words in the Scrabble and Words With Friends dictionaries. The word count by length is: 2 two-letter words.