directest

direct in spatial dimensions; proceeding without deviation or interruption; straight and short;
having no intervening persons, agents, conditions;
straightforward in means or manner or behavior or language or action;
in a straight unbroken line of descent from parent to child;
moving from west to east on the celestial sphere; or--for planets--around the sun in the same direction as the Earth
similar in nature or effect or relation to another quantity;
(of a current) flowing in one direction only;
being an immediate result or consequence;
in precisely the same words used by a writer or speaker;
lacking compromising or mitigating elements; exact;

directest is a valid Scrabble (US) TWL word

directest is a valid Scrabble Word in Merriam-Webster MW Dictionary

directest is a valid Scrabble Word in International Collins CSW Dictionary

directest is a valid Words With Friends word