Princeton's WordNet

1. child, kid, youngster, minor, shaver, nipper, small fry, tiddler, tike, tyke, fry, nestling(noun)

   a young person of either sex

   Synonyms:
   chela, kid, nestling, tiddler, pip-squeak, claw, electric razor, nipper, shaver, pincer, kidskin, boor, peasant, barbarian, squirt, churl, tyke, child, minor, tike, small fry, youngster, electric shaver, baby bird, fry, baby

   Antonyms:
   parent

2. child, kid(noun)

   a human offspring (son or daughter) of any age

   Synonyms:
   nestling, tiddler, fry, child, youngster, baby, shaver, tyke, nipper, minor, kid, small fry, kidskin, tike

   Antonyms:
   parent

3. child, baby(noun)

   an immature childish person

   Synonyms:
   nestling, tiddler, fry, babe, sister, child, youngster, baby, shaver, tyke, nipper, minor, kid, small fry, tike, infant

   Antonyms:
   parent

4. child(noun)

   a member of a clan or tribe

   Synonyms:
   nestling, tiddler, fry, youngster, baby, shaver, tyke, nipper, minor, kid, small fry, tike

   Antonyms:
   parent