happiest

happiest is a valid word in Scrabble and Words With Friends. It has 8 letters and scores 15 points before any board bonuses (h 4 + a 1 + p 3 + p 3 + i 1 + e 1 + s 1 + t 1).

It is an anagram of 1 other word: epitaphs.

“HAPPIEST” on Wiktionary