Filler words are words or phrases that people use in conversation to fill pauses or gaps while thinking. Common examples include "um," "uh," "like," and "you know." They often serve no grammatical purpose but can help speakers manage the flow of conversation and signal that they are still speaking. While filler words can make speech sound more casual, excessive use may distract listeners or make the speaker seem less confident. In public speaking or formal writing, reducing filler words can enhance clarity and professionalism, making the message more impactful for the audience.