I found this sentence from a book (English book):
Let's sit somewhere else; they always talk shop over lunch, and it bores me rigid.
The definition of this word is stiff or inflexible according to some dictionaries. I think that word has the alternative meaning in the sentence above. There's also a discussion here discussing the usage of rigid, but I still haven't got any clue. As far as I can understand, I guess it's to emphasize something when we use really, right.
For instance, the last clause (in my opinion) can be replaced by:
... it really bores me.
Is my assumption correct?