check out

1.  Record one's departure from a hotel by paying the bill, or from a conference or other function, as in As soon as my bags are packed I'll check out of the motel. [Early 1900s]
2.  Leave hurriedly, make a quick exit, as in The minute I get paid I'm checking out. [Slang; 1920s]
3.  Die, as in When he got cholera, he was sure he'd check out. [Slang; 1920s]
4.  Withdraw an item after recording the withdrawal, as in I'll check out the tapes on your library card. [1930s]
5.  Record, total the prices, and receive payment for a purchase, as in The cashier checked out and bagged my groceries in record time.
6.  check something or someone out. Investigate or evaluate something or someone; observe carefully. For example, I don't know if you'll like the film; check it out yourself, or That man who's staring is probably just checking us out. [Slang; mid-1900s]
7.  Pass close inspection, as in That rattle made me suspicious, but the repairman said the machine checked out completely.

The verb has 6 meanings:

Meaning #1: examine so as to determine accuracy, quality, or condition
  Synonyms: check, check up on, look into, suss out, check over, go over, check into

Meaning #2: announce one's departure from a hotel
  Antonym: check in (meaning #1)

Meaning #3: be verified or confirmed; pass inspection
  Synonym: check

Meaning #4: trace
  Synonym: run down

Meaning #5: withdraw money by writing a check
  Synonym: cheque

Meaning #6: try to learn someone's opinions and intentions
  Synonyms: sound out, feel out