Quixotic — exceedingly idealistic; unrealistic and impractical : Everyone laughed at Jeff’s quixotic resolution to read more Cervantes this year.
Mendacious — not telling the truth; lying : IMO, the number of guys Carol claims she has slept with is mendacious.
Cockamamie — ridiculous; implausible : Did Grandpa ever tell you the story of how he slept with President Eisenhower’s wife? It’s cockamamie!
Folderol — trivial or nonsensical fuss : I used to get stressed out over the smallest things. Then, I started taking Folderol.
Jackanapes : an impertinent person; a rapscallion or hooligan : Those goddamn jackanapes masturbated all over my car again!