duck

1 duck /ˈdʌk/ noun
plural ducks
1 duck
/ˈdʌk/
noun
plural ducks
Britannica Dictionary definition of DUCK
1 
[count] : any one of many different kinds of birds that swim and have a flat beak, a short neck, a heavy body, short legs, and webbed feet — often used before another noun — see color picture on this page
2 
[count] : a female duck — compare drake
3 
[noncount] : the meat of a duck used as food
4 
[count] informal : a person who you think is lucky, unusual, etc.
5 
British, informal or ducks — used to address someone you love

like a duck to water

informal
: very quickly or easily

water off a duck's back

— see 1water
2 duck /ˈdʌk/ verb
ducks; ducked; ducking
2 duck
/ˈdʌk/
verb
ducks; ducked; ducking
Britannica Dictionary definition of DUCK
1 
a  [no object] : to lower your head or body suddenly to avoid being seen or hit — often + down
b  [+ object] : to lower (your head) suddenly
c  [+ object] : to avoid (something, such as a punch) by lowering your head or body suddenly
2 
[+ object] : to avoid (something or someone you do not want to see or deal with)
3 
always followed by an adverb or preposition, [no object] : to move quickly
4 
[+ object] British : to push (someone or something) underwater : dunk

duck out

[phrasal verb] informal
: to leave suddenly and usually without telling anyone that you are leaving — often + on or of
— often used figuratively