The child in the family, often the second oldest, who is often the most unhappy in life. The "favorite child" will often put others down in attempts to make them feel better from the impending darkness inside that reminds them of how alone they are.
Being the least favorite child means you either:
a) Have a younger sibling b) Are less loved
c) Use the term to irritate your parents as they supposedly "love you equally"
My mother said there is no such thing as a least favorite child, and that she loves us equally. Yet she obliviously loves my brother/sister more.
