bull.

The noun has 9 meanings:

Meaning #1: uncastrated adult male of domestic cattle

Meaning #2: a large and strong and heavyset man
  Synonyms: bruiser, strapper, Samson

Meaning #3: unacceptable behavior (especially ludicrously false statements)
  Synonyms: bullshit, Irish bull, horseshit, shit, crap, bunk, bunkum, buncombe, guff, rot, hogwash, dogshit

Meaning #4: a serious and ludicrous blunder

Meaning #5: (informal) uncomplimentary terms for a policeman
  Synonyms: cop, copper, fuzz, pig

Meaning #6: an investor with an optimistic market outlook
  Antonym: bear (meaning #2)

Meaning #7: the center of a target
  Synonym: bull's eye

Meaning #8: a formal proclamation issued by the pope (usually written in antiquated characters and sealed with a leaden bulla)
  Synonym: papal bull

Meaning #9: mature male of various mammals of which the female is called `cow'; e.g. whales or elephants or especially cattle

The verb bull has 4 meanings:

Meaning #1: push or force
  Synonym: bull through

Meaning #2: try to raise the price of stocks through speculative buying

Meaning #3: talk through one's hat
  Synonyms: bullshit, fake

Meaning #4: advance in price, as of stocks

The adjective bull has one meaning:

Meaning #1: characterized by rising prices