1. something is very surprising and hard to believe.

He's coming here tonight? No shit!

2. the truth.

This is no shit — we're going to have the money for you tomorrow.

• a backseat driver
• a bad apple
• a bad egg
• a bad workman blames his tools.
• a bag lady
• a bag of bones
• a baker's dozen
• a balancing act
• a ball and chain
• a ball-breaker
• a ballpark estimate
• a ballpark figure
• a balls-up
• a banana republic
• a banana skin
• a Band-Aid
• a bang up job
• a baptism by fire
• a baptism of fire
• a bargaining chip
• a basket case
• a battle of nerves
• a battle of wills
• a battle of wits
• ABCs of