full of it

Talking nonsense, as in He claims to have fixed the dock, but I think he's full of it . This usage is a euphemism for ruder idioms like full of crap .

Also, full of the devil . Mischievous, naughty. For example, The youngsters were full of it today, giving the teacher a hard time , or Bill is full of the devil, hiding his roommate's clothes and teasing him mercilessly .