Examples of Same Meaning, Different Words (Synonyms):
General:
* Happy: Joyful, cheerful, delighted, ecstatic, blissful
* Sad: Depressed, sorrowful, mournful, gloomy, heartbroken
* Big: Large, enormous, gigantic, huge, immense
* Small: Tiny, miniature, petite, little, diminutive
* Start: Begin, commence, initiate, embark
* Finish: End, conclude, terminate, complete
* Good: Excellent, wonderful, superb, fantastic, brilliant
* Bad: Terrible, awful, horrible, dreadful, atrocious
More specific:
* Courageous: Brave, valiant, bold, fearless
* Confused: Bewildered, perplexed, puzzled, disoriented
* Angry: Furious, enraged, irate, incensed
* Excited: Thrilled, enthusiastic, energized, animated
* Lazy: Indolent, sluggish, lethargic, inactive
* Clever: Intelligent, bright, sharp, astute, ingenious
* Beautiful: Gorgeous, stunning, exquisite, lovely, attractive
* Ugly: Hideous, repulsive, grotesque, unsightly, unattractive
Idioms:
* Kick the bucket: Die
* Spill the beans: Tell a secret
* Hit the road: Leave
* Break a leg: Good luck
Formal vs. Informal:
* Formal: Use "begin" or "commence" instead of "start"
* Informal: Use "chill" or "hang out" instead of "relax"
Note: Synonyms often have subtle differences in meaning, connotation, or usage.