"Blow smoke"
Definitions from Idioms.TheFreeDictionary.com:
blow smoke:
To deceive others.
"He wanted everyone to believe he had a lot of experience, but I think he was just blowing smoke."
Cambridge Dictionary of American Idioms Copyright ©2003.
blow smoke (American):
To say things that are not true in order to make yourself or something you are involved with seem better than it is.
"The team put on an unbelievable performance. I'm not just blowing smoke - they were great."
Cambridge Idioms Dictionary, 2nd ed. Copyright ©2006.
blow smoke:
- tv. To state something in a way that conceals the truth. (see also smoke and mirrors.) "She is a master at blowing smoke. She belongs in government."
- tv. To smoke marijuana. (Drugs.) "Frank sits around blowing smoke when he’s not selling." McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright ©2006
blow smoke:
- To speak deceptively.
- To brag or exaggerate. American Heritage® Dictionary of the English Language, Fifth Edition. Copyright ©2016