How do I recognize a traded character?
Recently traded characters are marked in numerous ways. Recently traded means that the character has been transferred in the last 30 days. After this 30 day period, the character will no longer be marked.
Ingame, every recently traded character receives the addition "(traded)" behind their name when writing a chat message. A right-click on the chat message offers the context menu entry "Traded Character" which reveals how many days ago the character was traded. Furthermore, items whose text description can be altered (e.g. letters) display a hint that the text was last changed by a character which was recently traded.
On the website, players will be marked with "(traded)" in the characters section. In the forums, recently traded characters will receive the addition "traded" as well as a tooltip below their name when posting. Posts written by this character before the trade will also be marked "traded", but can no longer be reported. The character's post count is reset as well.
Source: https://www.tibia.com/news/?subtopic=latestnews&id=5692#faq11