Take a pledge is an expression that means to make a solemn commitment or PROMISE. The two crossword solutions for this term are VOW (3 letters) and PROMISE (7 letters). A VOW is a formal declaration of a PROMISE, usually made in a religious context, while a PROMISE is a declaration or assurance that one will do a particular thing or that a particular thing will happen. Both words are used to describe a commitment to do something or to refrain from doing something.