From Tar Valon Library
Wilder is the term used, especially by Aes Sedai to describe people who learned how to channel on their own. As Aes Sedai believe they are the only people to actually know how to train anyone, they also use the term for anyone who was not trained by the White Tower, such as Windfinders , Wise Ones (ACoS, Ch. 40) and damane (WH, Ch. 8), (WH, Ch. 35) and historically saw no difference between the two. Many Aes Sedai dislike wilders (TDR, Ch. 22; TFoH, Ch. 18; KoD, Prologue) and it can actually count against a person for their place in the hierarchy (LoC, Ch. 30). People who do not learn to channel under supervision only have a twenty five percent chance of survival, so wilders are fairly uncommon. Such people often have a block (LoC, Ch. 8), so that they do not know they can channel, but if this can be broken down, they are often very accomplished channelers. They often also have a trick, often a form of compulsion, that they do without realising (LoC, Ch. 8); TPoD, Prologue). Wilders typically avoid the Power and none has ever been recorded as having an object of the Power on them (ACoS, Ch. 17)
“Oh, I know you learned to channel under Aes Sedai teaching, but you are still a wilder. A wilder in spirit, a wilder in ways. You have vast potential, else you would never have survived in there tonight, but potential changes nothing. I do not believe you will ever be part of the White Tower, not in the way the rest of us are, no matter on which finger you wear your ring (Elaida, to Egwene, The Dragon Reborn, Chapter 23).
"A wilder, of course, yet still sensible" (Elaida on Tarna, A Crown of Swords, Prologue).
"Almost every wilder who came to the White Tower for training, both true wilders, who really had begun teaching themselves, and girls who merely had started touching the Source because the spark born in them had quickened on its own; for some sisters, there was no real difference nearly every one of those wilders had created at least one trick for herself, and those tricks almost invariably fell under one of two headings. A way to listen in on other people's conversations, or a way of making people do as they wanted." (Verin, The Path of Daggers, Prologue).