A nonsensical dress code that people slap onto events, parties, and workplaces.
Completely down to interpretation; this always causes confusion and often spectacular results.
A mixture between smart and casual - should not be taken literally.
Andy- "What's the dress code tonight?"
Bob- "Smart Casual"
Andy- "Well what the hell does that mean?!"
Jim- "Hey, is Andy wearing jogging bottoms with that blazer?!"
Bob- "Yeah it's Smart Casual