11 letters · 15 points in Scrabble
verb work together on a common enterprise of project
verb cooperate as a traitor
originBack-formation from collaborator, from French collaborateur, or else modeled on French collaborer or directly from Late Latin collabōrātus, past participle of collabōrāre. Displaced native Old English efnwyrċan.
Etymology from Wiktionary, CC BY-SA 3.0