All 4 Uses

resignation
in
A Thousand Splendid Suns
(Edited)

the American president Richard Nixon had resigned over a scandal.
p. 64.6 *

resigned = given up a position or job
Mariam, who had never heard of Nixon, or the scandal that had forced him to resign, did not say anything back.
p. 64.7

resign = quit (a position or job)
On her face, a look of concession. Of resignation.
p. 189.8

resignation = acceptance of something undesired as unavoidable
And so Laila has resigned herself to moving on.
p. 411.2 *

resigned = accepted something undesired as unavoidable

Definitions:

(1) (resignation as in: submitted her resignation)
to quit -- especially a job or position; or a document expressing such an act
(2) (resignation as in: accepted it with resignation)
acceptance of something undesired as unavoidable or the lesser of evils
(3) (meaning too rare to warrant focus)
To resign can also more specifically mean to surrender or give up as in "I was clearly going to lose the chess game, so I resigned;" or "She resigned all pretense."