Can a Thief Steal a Really Impressive Title?
Thieves can only steal Items. An Item either has a gold piece value or &quot;No value&quot; printed in the corner. Really Impressive Title has neither of these, so it is not an Item, so it can't be stolen.
Note that in earlier editions of Munchkin, this card was actually misprinted, and confusingly did in fact say &quot;No Value&quot;. Per the official Errata, this is corrected in the 19th printing:

Corrected Errata
Corrected in the 19th Printing
Really Impressive Title is not an item, so it should not say &quot;No Value&quot;