End-to-end encryption prevents knowing what is written
All WhatsApp conversations are encrypted from end to end, it is something that the applications are responsible for remembering almost every moment. This makes chats 100% private, at least as long as the conversation stays there: WhatsApp finds it impossible to know what is said, which emojis are attached, the stickers or with what reaction a message is answered. This also applies to concrete words.
WhatsApp does not have a specific list of prohibited words because cannot extract them from conversations to analyze everything that is said: End-to-end encryption prevents this. Nor does any reference to prohibited terms appear in the conditions of use of the application or in the help. Quite simply, WhatsApp cannot detect what you write in conversations, whether they are private or in groups (all are encrypted by default). Therefore, it cannot block your account just because you write something.
There are no banned words and you can’t be locked out of your account just because you typed them. Now, that does not mean that WhatsApp stops prosecuting uncivic and/or criminal behavior, since it does clearly specify that you must use the applications responsibly, respectfully and following the terms of use. As WhatsApp itself specifies:
“Our Terms of Service prohibit, among other things, the posting of false material and behavior that is unlawful, threatening, harassing, hateful, or racially or ethnically offensive.”
WhatsApp clearly prohibits certain behaviors when writing. Pederasty, threats, harassment and other illegal attitudes are strictly prohibited (and they are reportable), but there is no automatic way for WhatsApp to detect the topics that are discussed in the chats. Now, there is a tool with which you would have access to those conversations.
If they report you WhatsApp will read the messages
WhatsApp does not read the conversations and could not do so even if it wanted to, but it does have access to certain messages when they are reported. Using that tool, the “Report” tool, Any WhatsApp user can report those conversations and/or contacts that, based on their criteria, violate the rules of use of the platform. Therefore, if you wrote according to what terms and another user reported it, you could get into trouble. And the blocking of the WhatsApp account would be the least of them.
What happens when there is a report? WhatsApp itself specifies it:
WhatsApp receives the last five messages that person or group sent you, but does not notify the senders. WhatsApp also receives the identification of the reported user or group, information about when the message was sent, and the type of message sent (image, video, text, etc.).
If there is behavior that violates the terms of service, WhatsApp could block your account. In general, I would do it temporarily first and, depending on the seriousness of what was reported, you could stay without a WhatsApp account forever. Moreover, this reported information can end up in the authorities, as specified by the platform itself:
‌We share information with law enforcement and others when a person’s vital interests require protection, such as in emergencies. These vital interests include the protection of life and physical or mental health, welfare or integrity, both yours and others.
One last detail to mention concerns everything that is not included in end-to-end encryption; how are the profile photos, group names or descriptions. WhatsApp automatically analyzes this information and contrasts it with databases such as the Child Sexual Abuse Material (CSAM) database. The platform fights against child exploitation and actively collaborates with the authorities: any allusion you make in these areas of WhatsApp can be expensive. Be very careful joking around.