find out

1.  Discover through examination or inquiry, as in You can find out his phone number by looking in the book. [Mid-1500]
2.  Expose, detect the true nature or character of, especially in an offense. For example, Cheaters risk being found out. [c. 1700]

Definition: discover, learn
Antonyms: conceal, cover, hide

The verb has 4 meanings:

Meaning #1: after a calculation, investigation, experiment, survey, or study
  Synonyms: determine, find, ascertain

Meaning #2: get to know or become aware of, usually accidentally
  Synonyms: learn, hear, get word, get wind, pick up, get a line, discover, see

Meaning #3: find out, learn, or determine with certainty, usually by making an inquiry or other effort
  Synonyms: determine, check, see, ascertain, watch, learn

Meaning #4: trap; esp. in an error or in a reprehensible act
  Synonym: catch out