growl.js is a Game Rule Oriented Word List presented in JavaScript.

growl.find(word) returns the level number of word, or false if not found.

Only English words of two or more letters that can be properly spelled
using only the lowercase letters a-z are included.

Levels 1-5 represent increasingly difficult/uncommon words.

Level 6 adds nearly all remaining words that anyone would consider valid,
but it includes many words that many people would not consider valid; so
include level 6 when validating user words but not when generating words.

Levels 1-5 are based on the most common American spellings; British,
Canadian and other variant spellings are typically included at level 6.