It is only in the late twentieth century, that this term was used in relation to Chinese martial arts by the Chinese community. In the Western popular culture, the term "Kung fu" is often erroneously used as an umbrella term when specifically referring to Chinese martial arts. The Oxford English Dictionary defines the term "kung-fu" as "a primarily unarmed Chinese martial art resembling karate." This illustrates how the meaning of this term has been changed in English. The origin of this change can be attributed to the misunderstanding or mistranslation of the term through movie subtitles or dubbing.
In Chinese, gōngfu (功夫) is a compound of two words, combining 功 (gōng) meaning "work", "achievement", or "merit", and 夫 (fū) which is alternately treated as being a word for "man" or as a particle or nominal suffix with diverse meanings (the same character is used to write both). A literal rendering of the first interpretation would be "achievement of man", while the second is often described as "work and time/effort". Its connotation is that of an accomplishment arrived at by great effort of time and energy. In Mandarin, when two "first tone" words such as gōng and fū are combined, the second word often takes a neutral tone, in this case forming gōngfu. The word is also sometimes written as 工夫, this version often being used for more general, non-martial arts usages of the term.
Originally, practicing Kung Fu did not just mean to practice Chinese martial arts. Instead, it referred to the process of one's training - the strengthening of the body and the mind, the learning and the perfection of one's skills - rather than to what was being trained. It refers to excellence achieved through long practice in any endeavor. This meaning can be traced to classical writings, especially those of Neo-Confucianism, which emphasize the importance of effort in education.
In the colloquial, one can say that a person's kung fu is good in cooking, or that someone has kung fu in calligraphy; saying that a person possesses kung fu in an area implies skill in that area, which they have worked hard to develop. The colloquial use of the term has thus returned to the original literal meaning. Someone with "bad kung fu" simply has not put enough time and effort into training, or seems to lack the motivation to do so. Kung fu is also a name used for the elaborate Fujian tea ceremony (kung fu cha).
However, the phrase 功夫武術 (kung fu wu shu) does exist in Chinese and could be (loosely) translated as 'the skills of the martial arts'.