Definition: to be important or famous, but in a small group (note: this is not a positive idiom — if you tell someone they are a big fish in a small pond, they will get angry at you!)
Examples:
I am a top manager at this company, but the company is really small. I am tired of being a big fish in a small pond — I want to go work at a large international company.
He thinks he is really important, but outside his group, no one knows him. He is just a big fish in a small pond.
Definition: to attract a lot of attention; to get noticed Examples: Everyone is talking about the new movie. It really made a splash. That new book is really popular. The author is on all the talk shows. She really made a splash.
Definition: to create a significant impression; to cause trouble, to be disruptive Examples: At your new job, be sure to speak up at meetings. You want to make waves right from the start. I didn't know anyone at the dinner party, so I kept quiet. I didn't want to make...
Definition: to say something awkward or inappropriate Examples: I saw my boss on the street yesterday. He was with a woman. I said I loved his wife's dress, but she wasn't his wife. She was his girlfriend. I definitely put my foot in my mouth that time. I thought the...