if you are out for blood, you are determined to find someone to attack or blame for something.

These people are out for blood and if they find out you're involved you're in serious trouble.

• not be someone's cup of tea
• not be someone's department
• not be the end of the world
• not be the full quid
• not be the marrying kind
• not be the only pebble on the beach
• not be up to much
• not be up to scratch
• not be worth a dime
• not be worth a fig
• not be worth a hill of beans
• not be worth the paper it's printed on
• not be worth the paper it's written on
• not be worth the paper they're printed on
• not be worth the paper they're written on
• not be your bag
• not be your brother's keeper
• not break the bank
• not breathe a word
• not budge an inch
• not by a long shot
• not by any stretch
• not by any stretch of the imagination
• not care a fig
• not care a hoot