be full of shit/crap
be full of crap
rude slang To be unreliable or ridiculous (usually because one makes unfounded or nonsensical statements). You can't listen to Sean, he's full of crap! He doesn't know any more about robotics than we do. Oh, Stephanie is full of crap—she threatens to move out all the time. Quit trying to convince me that pigeons can swim—I know you're full of crap!