siffical
To appear overly intelligent through the use of unusually long winded and scientific words. A siffical person may be also called a "siffic".
Jeeves: "According to the exoglylocal society of infinitive law, I hearby deem you to be of a rather curious disposition!"
Sara:"Bro, you're way too siffical."
Sara:"Bro, you're way too siffical."