completely wrong, false, or worthless.

He promises me things all the time but he's full of crap.

Related vocabulary: full of it

• beauty sleep
• be a waste of space
• be a weight off mind
• be a weight off shoulders
• be a weight off your mind
• be a weight off your shoulders
• be a writer in the making
• be backed into a corner
• be back in harness
• be back on the rails
• be backward in coming forward
• be bad news
• be bag
• be banging head against a brick wall
• be banging your head against a brick wall
• be bang on
• be barking mad
• be barking up the wrong tree
• be batting a thousand
• be batting on a sticky wicket
• be baying for blood
• be before time
• be before your time
• be behind the eight ball
• be behind the times