The flat was what he imagined people called ‘cosy’, but what his mother would have disparaged as ‘untidy’ or ‘cluttered’, which in Narcissa-speak was on par with ‘war zone’, ‘ebolic’, and ‘third world-esque'.

And since you are indirectly quoting Narcissa, you could probably say:

The flat was what he imagined people called ‘cosy’, but what his mother would have disparaged as untidy or cluttered, which in Narcissa-speak was on par with ‘war zone, ebolic, and third world-esque'.

Cowboys doomed and a Gorilla? now that's a story!