"Not a bit of it" is an idiomatic expression that means "absolutely not" or "not in any way." Some synonyms for this phrase include "not at all," "by no means," "no way," and "not in the slightest." In addition, you can use phrases like "certainly not," "definitely not," or "under no circumstances" to convey the same meaning. These phrases are useful when you want to make a strong and clear denial of something. They can be used in a variety of situations, whether you are rejecting a proposal, disagreeing with a statement, or clarifying a misunderstanding.