A person who has accepted and become
complacent to the deprivation of that person's role or
identity.
The term is a shortened take of “cuckold” which is defined as “A husband of an adulterous wife.” The implicit message there, then, is that anyone called a “cuck” is someone perceived as
emasculated.
A cuckquean, is the gender-opposite of a cuckold, is a woman with an adulterous husband.