An explanation about this has just been added to the Command1 section notes.
Paid! and Peidiwch! are the informal singular and formal/plural command forms of the verb peidio - 'refraining from, to refrain from', but translated into English as 'Don't!' They are usually, but not always, followed by the preposition â/ag:
- Peidiwch â siarad! - Don't talk!
- Paid â mynd allan heb dy allweddi eto, Dewi - Don't go out without your keys again, Dewi!
- Paid ag edrych arno fe! - Don't look at him!