A word's being regional, or dated, does not necessarily disqualify it from inclusion in our acceptable words. However, I certainly feel more comfortable about a word if it is listed in general dictionaries.
Razoo passes this test: it is in the Oxford Dictionary of English and the Collins English Dictionary, as well as various dictionaries from Australia and New Zealand.
It may be that the word got its common status in Chi because I didn't realise it was specific to Australia and New Zealand. Green's Dictionary of Slang identifies it as originally N.Z., then Aus/N.Z., but almost all the usage examples given are from Australian sources. This slang dictionary is freely accessible online, and I'd recommend anyone interested in this word to read
the entry, which has a multitude of quotations using
razoo.
The word has occasionally been used by people from elsewhere. The Scottish writer John Niven, in a 2018 article in the
Daily Record, wrote: "Nothing, darling. Not a farthing. Not a groat. Not a single brass razoo." However the word's currency (so to speak) is 99% Down Under, where it was first coined (so to speak).
Razoo will be treated as a rare word in future.
While looking into this, I learnt that another word with a similar meaning,
skerrick, is also mostly used in Australia and New Zealand, though probably derived from British regional terms. Like
razoo,
skerrick is often used in a negative sense: "We have seen not a skerrick of remorse from Scotty or his cronies..."
Skerrick is playable in Chi, as a rare word.