While an Erfworlder will instinctively understand the words "kill" and "death" to have the same meaning, it is not a normal part of their vocabulary and they will find it vulgar if they hear it from someone else, like a Stupidworlder.
Croaked units leave bodies, which exist as physical objects for a short time after croaking. Bodies disappear at the start of the next turn that their side has, unless moved/claimed (e.g. uncroaked, reanimated as golems, eaten, used for something else like the teddybearskin rug and mounted gwiffon head in Parson's room)Erf-b1-p035. In the event that their side is eliminated, unclaimed bodies disappear at the next nightfall.
Croaked units' bodies have X's in place of their eyes.
Due to the facts that Wanda had to retrieve the body of Manpower Erf-b1-p3 and later said that they had to capture Ossomer, rather then croak and drag the body over to GK's hex afterwardsErf-b2-p6, there is speculation that moving a dead body from hex to hex causes it to be impossible to uncroak/decrypt. The evidence either way is weak though as somebody was going to have to retrieve Manpower's body so it may as well have been Wanda who could uncroak it immediately; in Ossomer's case, Ansom wanted Ossomer alive to try and turn him, Wanda decided she wasn't going to bother and decrypted him instead.
Real World References
When used as a verb, one of the meanings of "croak" is slang for "die" or "kill".
The Carp module in the Perl programming language includes a
croak function as an alternative to the built-in
die function. Both terminate evaluation of the script and print an error message, with subtly different effects.