I have never heard the unmodified word "oath" used to indicate anything less than positive. Only very rarely is it used in any negative sense, and then almost a

I have never heard the unmodified word "oath" used to indicate anything less than positive. Only very rarely is it used in any negative sense, and then almost always with some sort of descriptor -- "Bloody oath", as you say Are you from AU by chance? Urban Dictionary seems to indicate 'oath' is slang over there https://www.urbandictionary.com/define.php?term=oath https://www.urbandictionary.com/define.php?term=oath