To fight tooth and nail - to use a lot of effort to oppose someone or achieve something. Example - "I'm going to fight tooth and nail for that promotion"
To burn bridges - to make decisions that cannot be changed in the future; to permanently and unpleasantly end your relationship with a person or organisation. Example - "If you drop out of school now, you'll be burning your bridges behind you"
The world's smallest violin -When someone is whiningand you are tired of hearing it, you can play the world's smallest violin to provide musical ambiance to dramatize their annoying whine. This is accomplished by rubbing your index finger and thumb together and saying, "This is the world's smallest violin, and it's playing just for you."
To sound out - to carefully found out what someone thinks or knows. Example - "I don't know what Jane thinks about your suggestions but I will sound her out"
Harebrained - ill-judged; very silly or foolish. Example - "It was a harebrained idea to go for a hike in an area where grizzly bear attacks had recently been reported"
Dilettante - a person who cultivates an area of interest, such as the arts, without real commitment or knowledge; a dabbler. Example - "You can always tell a true expert from a dilettante"
To show somebody the ropes - to explain to someone how to do a job or activity. Example - "The new secretary started today so I spent most of the morning showing her the ropes"
Marauding - going from one place to another killing or using violence, stealing, and destroying. Example - "Witnesses reported gangs of marauding soldiers breaking into people's houses and setting fire to them"