The word "falterer" has several synonyms that can be used in its place in various contexts. One possible replacement is "hesitator," denoting someone who hesitates or shows reluctance in taking action. Another synonym is "ditherer," which refers to a person who is indecisive or uncertain. "Waverer" is another word that connotes a lack of resolve or steadiness. "Vacillator" is a term used to describe someone who is indecisive or changes their mind frequently. Finally, "indecisive person" is a more general term that can be used to describe someone who struggles to make decisions or take decisive action.