Definitions of shit:

• noun:   a coarse term for defecation

  Example: "He took a shit"

• noun:   obscene terms for feces
• noun:   something of little value
• noun:   obscene words for unacceptable behavior

  Example: "I put up with a lot of bullshit from that jerk"

• noun:   insulting terms of address for people who are stupid or irritating or ridiculous
• noun:   a small worthless amount
• verb:   have a bowel movement
• verb:   give away information about somebody