Basic Synonyms (Words with very similar meanings):
* Happy: Joyful, cheerful, delighted, glad
* Sad: Depressed, sorrowful, unhappy, mournful
* Big: Large, huge, enormous, gigantic
* Small: Tiny, little, miniature, petite
* Good: Excellent, wonderful, fantastic, great
* Bad: Terrible, awful, horrible, dreadful
Near Synonyms (Words with slightly different shades of meaning):
* Angry: Furious, enraged, irate, indignant
* Fearful: Afraid, scared, terrified, anxious
* Strong: Powerful, robust, sturdy, mighty
* Interesting: Fascinating, captivating, intriguing, absorbing
* Clever: Intelligent, bright, smart, astute
Formal/Informal Synonyms (Words with similar meanings but different formality):
* Formal: Begin, commence, initiate, embark on
* Informal: Start, kick off, get going, get started
* Formal: Angry, incensed, outraged
* Informal: Mad, ticked off, pissed off
Antonyms (Words with opposite meanings):
* Hot: Cold
* Up: Down
* Light: Dark
* Happy: Sad
* Strong: Weak
Words with Different Connotations (Words with similar meanings but different emotional associations):
* Cheap: Inexpensive (positive connotation), cheap (negative connotation)
* Thrifty: Frugal (positive connotation), stingy (negative connotation)
* Determined: Resolute (positive connotation), stubborn (negative connotation)
Note: Synonyms are not always interchangeable. The specific context of a sentence often determines the most appropriate word to use.