The term "humming haw" refers to the act of hesitating or being indecisive. Synonyms for this phrase include vacillating, dithering, wavering, hesitating, stalling, and procrastinating. These words all describe a lack of certainty or a delay in making a decision. Other similar words that could be used include equivocating, fencing, pussyfooting, and hemming and hawing. It's important to note that while some of these words may have slightly different connotations, they all describe a similar behavior of being unsure or indecisive. Being aware of these synonyms can help writers and speakers more effectively convey their intended message.