Viper: replacing text?

[Elena]

Hello,

how do I replace text with previous kill?

That is: I kill (or copy) a word, then travel to another word and I'd
like to replace the latter with the former. Currently I paste the
first word, move a character to the right and kill the second word,
but I don't think that's the faster way to do it.

Of course, I'm not talking about replacing text in the context of
search and replace.

Thanks.