Late 17th century: from Dutch snoek (see snoek).

• cock from Old English:

  The ancient root of the word cock was probably suggested by the sound the bird makes. The same root is likely to have given us chicken as well. If you are cock-a-hoop you are extremely pleased, especially after some success or triumph. The expression dates from the 17th century and comes from an earlier phrase set cock a hoop. Cock here may be used in the sense of a tap for stopping the flow of liquid, so that the expression refers to turning on the tap of a beer barrel and allowing beer to flow freely before a drinking session. A cock-and-bull story is a ridiculous and implausible tale. The expression ‘talk of a cock and a bull’ is recorded from the early 17th century, and apparently refers to some rambling story or fable, a ‘shaggy dog story’, which is now lost. To cock a snook, first recorded in 1791, is to show open contempt or lack of respect for someone or something, originally by touching your nose with your thumb and spreading out your fingers. Cock here means ‘to stick out stiffly’, but the origin of snook is not known. Because it is such an unfamiliar word, people have often taken to saying snoot (slang for ‘nose’) instead of snook. See also cox

Late 18th century: of unknown origin.