If we're talking about Java, it's very rare that you need to distinguish a
Class object as being distinct from an interface. They're all basically types, and calling them all classes is reinforced by the fact that there is only a
Class class (with an
isInterface() method), and they are compiled to
.class files. So I've seen
clazz is pretty common.
If you did need to reference something knowing full well that it was an interface, and you wanted to convey that fact, then you'd have to invent your own name; it's pretty unusual, and you only get conventions for frequently-used concepts.
If I felt compelled to select a name, then why not intyMcInterface? - seeing as how Boaty McBoatface topped the famous Name This Boat poll. Or you could call it sirDavidAttenborough, like they ended up doing, but you might get some WTFs for that.