I have write an Antonym and Synonym for each word. Nouns

1. biped---quadruped, person

2. centipede---millipede, worm

3. millipede---unipede, creepy-crawly

4. pedal---foot iever (couldn't find an antonym)

5. pedicure--manicure, beauty treatment

6. quadruped--biped, tetrapod

You're on the right track. This is an excellent source for synonyms and antonyms:

http://www.thesaurus.com

To find antonyms and synonyms for the given nouns, you can use a thesaurus or an online dictionary. These resources provide comprehensive lists of related words. Here are the antonyms and synonyms for each word:

1. Biped
- Antonym: Quadruped
- Synonym: Person

2. Centipede
- Antonym: Millipede
- Synonym: Worm

3. Millipede
- Antonym: Unipede (Note: "Unipede" is not a commonly used term. "Uniped" means having only one foot or leg, but it is not the direct opposite of a millipede.)
- Synonym: Creepy-crawly

4. Pedal
- Antonym: There isn't a single-word antonym for pedal. You could use a phrase like "hand lever" to imply the opposite.
- Synonym: Foot lever (Note: Pedal is more commonly used for describing foot-operated handles, but "foot lever" can be used as a synonym.)

5. Pedicure
- Antonym: Manicure
- Synonym: Beauty treatment

6. Quadruped
- Antonym: Biped
- Synonym: Tetrapod (Note: "Tetrapod" is a more scientific term that encompasses all animals with four limbs. It can be used as a synonym for quadruped in a general sense.)