Verb kennt inflection of kennen: third-person singular present second-person plural present plural imperative
was der Bauer nicht kennt, das frisst er nicht German Etymology Calque of German Low German wat de Buur nich kennt, dat frett he nich (“what the farmer doesn’t know, he won’t eat”). Compare also Dutch wat de boer niet kent, dat vreet hij niet.
kein Pardon kennen (irregular weak, third-person singular present kennt kein Pardon, past tense kannte kein Pardon, past participle kein Pardon gekannt, past subjunctive kennte kein Pardon, auxiliary haben) (idiomatic) to show no leniency or mercy, to not hold back (idiomatic) to not allow exceptions, to be strict
kenne (third-person singular present kennt, past tense kannt, past participle jekannt or gekannt) (most dialects) to know; to be acquainted with
seine Pappenheimer kennen (irregular weak, third-person singular present kennt seine Pappenheimer, past tense kannte seine Pappenheimer, past participle seine Pappenheimer gekannt, past subjunctive kennte seine Pappenheimer, auxiliary haben) (idiomatic) to know who one's dealing with
I know that "kein" is normally followed by an noun or noun phrase: "Ich habe keine Lust zu arbeiten." In this case "kein" can be translated to "no": "I ...
Are "keine" and "nicht" both okay in the following? If so, what's the difference? Walter und Lise sind keine/nicht Eltern.
The explanations you have encountered are not correct, and "Wir trinken keinen Wein" definitely does not have this special, short-term meaning. It's what people in beer-brewing regions say to express that they never drink wine. For the real difference, see the two top answers to the other question linked by Gerhard. Basically the idea is that nicht ein negates just the word ein (so is rarely ...