That's "nudist".
Short answer: yes.Longer answer: On private property, where there is no possibility of the nudists being seen by members of the general public, the answer would be "yes", other than...
It is illegal to use any type of horn that emits more than one tone, unless the tones are simultaneous. There are no exceptions.
Emergency vehicles on route are an exception.
Yes, it is legal to own one, but not to be in possession with it in the street. Also, you must have bought it before June 2004, because that's when they were made illegal to sell.