A drill instructor is a military personnel who trains cadets and new recruits. Synonyms for this term can include sergeants, trainers, mentors, instructors, and coaches. These experts have unique skills in molding and shaping military personnel to exhibit outstanding discipline, courage, and character during their service to the nation. Drill sergeants are some of the most critical personnel in the military training process and are known for their tough demeanor and ability to instill discipline. A drill instructor plays a vital role in preparing cadets and recruits for the rigors of military duty by providing guidelines, instructions, and leadership required for the smooth operation of military tasks.