There's not really any such thing as 'simple' when it comes to these words.
>saw some people simply said raising another child is cuck using the definition of cuckoo
Those people are wrong; the cuckoo is a brood parasite
, which is to say that it manipulates
other species into raising its young for it, to those species' detriment. If you've ever seen a grossly oversized cuckoo chick shoving its much tinier nestmates out of the way to get as much food from the haplessly-confused parent birds, or even shoving its nestmates out of the nest to die, then you understand the difference between it and something like voluntary human adoption, where someone willingly agrees to raise a child as though it were their own, or e.g. sperm donation, where the same thing happens.
A human man with an adulterous wife may well end up raising a child that he does not know is not his own
: Just like the cuckoo's victims, he has suffered brood parasitism and will unknowingly participate in his own bloodline's extinction. The insult becomes worse if the man does know he's been parasited and does nothing about it or otherwise participates. Women can't suffer parasitism in this way, changelings or other baby-swaps aside, so the "cuckquean" term is just a gender-swapped word that only takes the applicable parts i.e. adultery.
The word gets blurrier once you account for its use as an insult and all the different connotations and reasons that can have. Different people will usually disagree on these uses. For example, if someone can otherwise have children but is seen to have been manipulated into instead raising some other child "voluntarily", e.g. a fertile couple who choose to refrain from having children of their own and instead adopt a third-world orphan or something, one might level the "cuck" term at them if one perceives them as having done it in response to propaganda or something because the two components of manipulation
are present. A couple who discover that they can't have children themselves because of e.g. infertility and who decide to adopt an orphan instead
could not be accused of being cucks because neither manipulation nor extinction (at least, not extinction as a result of manipulation) apply.
>Does being stepparent/working on an orphanage makes you a cuck?
This is an incredibly ESL question. No, working at an orphanage does not make you a cuck. An orphanage worker has not been tricked into thinking the orphans are their own flesh and blood. Likewise being a step-parent, but again the insult use blurs the lines: If a man is perceived to have been manipulated
into parenting a woman's previous offspring in such a way that his own offspring either won't come to exist or will be disadvantaged, then he may find himself thought of as a cuckold.