The term CLEAN A CAR THOROUGHLY can be summarized by the word 'DETAIL, ' which is a 6-letter word. Detailing a car involves cleaning it inside and out, removing dirt, dust, and debris, and restoring its original shine. It also includes polishing, waxing, and vacuuming the interior and exterior of the car. Detailing a car is a more thorough process than simply washing it, and it can help maintain the car's value and extend its life.