Couldn't lie straight in bed Australia New Zealand informal
To be dishonest or deceptive; to lie a lot
Don't care about what John has said. That guy couldn't lie straight in bed.
No one believes what she is saying to be true as she couldn't lie straight in bed.
White lie
Seem to be very suspicious or morally unacceptable
Used to imply that someone is acting as if he or she is demure, innocent, sincere or reserved but they may be not
Very dishonest and deceptive
Used to allude that the last force, problem or burden which is seemingly minor and small causes a person, system or organisation to collapse or fail
Her husband's violent act last night was the straw that broke the donkey's back and she left him