Why a duck, in "ducked out"?

Solution 1:

Green’s Dictionary of Slang suggests that the usage of duck in duck out meaning:

  1. to make off, to leave, to abscond.
  • 1898 [US] F. Norris Moran of the Lady Letty 15: I’ve got to duck my nut or I’ll have the patrol boat after me.

derives from the old sense of duck meaning “to escape, to run off” as in:

do a/the duck (v.) (also do a duckaway)

  • 1896 [US] F. Hutcheson Barkeep Stories 173: ‘Dey ’re sore ’cause I do me duckaway an’ dey t’ink dey ’ll just take a shot at me anyhow’.