To influence someone is to affect their thoughts or actions in order to make them think or do something that might not agree with their original ideas. If you are an influence on someone, you inspire them to think or behave like you.
Ex: Melanie is so gullible that it's easy for others to influence her taste in fashion. Her parents, however, don't allow her to wear some of her choices to school.
Ex: My friends think I am a good influence on them, because, thanks to me, they eat better and exercise more. I am happy to set a good example for them to follow.
Driving under the influence means that you are operating a vehicle after consuming alcohol, and it's a crime. One's behavior can change under the influence of drugs, whether they are legal or illegal. An influential person is able to sway others, and his influence may be either positive or negative.
Ex: When my sister was still under the influence of the painkillers the dentist gave her to remove her wisdom teeth, she said the funniest things. We recorded her so she could enjoy it later.
Ex: The United States Senator from my hometown just won reelection and will begin serving her fourth term in the Senate in January. Her lengthy service in Congress makes her influential regarding issues that affect my state.
To dominate is to rule over or control. It can also mean to tower over, such as a skyscraper in a city or a tall tree in the landscape.
Ex: The Space Needle dominates the skyline of Seattle, and someone dining in the restaurant at the top of it can see the entire city.
Ex: When Larry Byrd played for the Boston Celtics, he dominated the offence, making several three-point shots per game and rarely missing a free throw.
A dominator is one who dominates, and the feminine form of the word is dominatrix. The idiom, to lord it over, means to dominate someone by behaving as if you are better than him and have the right to tell him what to do.
Ex: Michael Phelps is a dominator in the swimming pool, especially during the Olympics. He has 22 medals as evidence of his domination over other swimmers.
Ex: It's really no fun to play Monopoly with your sister Shelly. She always wins, and she lords it over us for days.