Here's a list of common words along with their more advanced synonyms:

Begin: Commence
End: Conclude
Smart: Intelligent
Happy: Content
Sad: Melancholy
Big: Enormous
Small: Minute
Tired: Fatigued
Pretty: Beautiful
Ugly: Unattractive
Rich: Affluent
Poor: Impoverished
Angry: Irate
Calm: Serene
Fast: Swift
Slow: Languid
Hard: Difficult
Easy: Simple
Funny: Hilarious
Serious: Solemn
Old: Ancient
New: Novel
Loud: Vociferous
Quiet: Hushed
Difficult: Challenging
Friendly: Amiable
Enemy: Adversary
Beautiful: Exquisite
Scared: Terrified
Courageous: Valiant