There are several synonyms that can be used in place of the word "bith," which refers to a small amount or quantity. Some alternative words include "smidge," "modicum," "speck," "trace," "dash," "hint," "whiff," "drop," "pinch," and "scant." These words are often used in informal or casual conversations to describe something that is minute or insignificant. However, it is important to use the appropriate synonyms based on the context and intended meaning of the sentence. It is also advisable to expand one's vocabulary by learning new words and their meanings to better express oneself in both written and spoken language.