Fast talking refers to the ability to speak quickly and fluently. However, when it comes to synonyms for this phrase, there are several options that can be used interchangeably, depending on context. One common synonym is "glib talking," which refers to someone who is able to speak convincingly and smoothly. Another option is "silver-tongued," which means having a persuasive and eloquent way of speaking. "Articulate" is another synonym that describes the ability to speak clearly and effectively. Finally, "smooth-talking" can imply someone who is using charm or flattery to manipulate others. Overall, these synonyms all convey the idea of being able to speak quickly and with ease.