“Tajemnica” can be translated into English as either “secret” or “secrecy”. The choice of which word to use and how to use it depends on what meaning you want to express.

For example, To jest tajemnica zawodowa may be translated as This is a professional secret.

Whereas, Obowiązuje mnie tajemnica zawodowa may be translated as I am bound by professional secrecy.

In the first example above “tajemnica” becomes the countable noun “secret”, referring to a piece of secret information. In the second example it becomes the uncountable noun “secrecy”, referring to the quality or condition of being secret.

I often see mistakes where, for example, a sentence like Niniejsze informacje podlegają tajemnicy zawodowej becomes This information is covered by professional secret or This information constitutes professional secrecy.

Such sentences are incorrect and make no sense in English. The sentences would be grammatically correct if they were written as follows: This information is covered by professional secrecy, or This information is a professional secret. However, in English the phrase “covered by professional secrecy” sounds very awkward, and the terms “professional secret / professional secrecy” are rarely used anyway.

The best way to translate the sentence is simply: This information is confidential or This is confidential information.

When you translate “tajemnica” it is therefore important to decide whether you wish to refer to one or more individual secrets, or to the concept / principle of secrecy. Next, it is useful to know whether your translation is the correct term in English or whether there is a recognised term that you should use instead. Here is a list of English equivalents of some common Polish terms:

• tajemnica adwokacka
  legal professional privilege (UK) attorney-client privilege (US); these terms describe the principle, not individual secrets. To refer to one or more individual secrets use information subject to legal professional privilege or privileged information
• tajemnica bankowa
  bank secrecy describes the principle; you may also refer to bank secrecy provisions. A bank secret describes an individual secret, or to refer to one or more individual secrets you may use information subject to bank secrecy
• tajemnica dziennikarska
  principle: journalistic privilege;
  one or more individual secrets: information subject to journalistic privilege or privileged information
• tajemnica handlowa
  usually used in countable form: a trade secret / trade secrets;
  the principle is referred to as trade secret protection or protection of trade secrets
• tajemnica lekarska
  principle: medical confidentiality / doctor-patient privilege / Hippocratic Oath;
  one or more individual secrets: information subject to medical confidentiality or confidential information
• tajemnica przedsiębiorstwa
  see “tajemnica handlowa”;
  also a business secret
• tajemnica państwowa
  individual secret: a state secret;
  one or more individual secrets: classified information; there is no particular term for the principle.

Typically there are several levels of classified information, depending of the degree of sensitivity – for more information see http://en.wikipedia.org/wiki/Classified_information

NB: Confidential information, privileged information and sensitive information are useful general terms that you may use if it is not necessary to convey a specific legal meaning.