väsa

Etymology
From.

Verb

 * 1) to hiss (especially of a snake)
 * 2) to wheeze
 * 1) to wheeze

Usage notes

 * An "ssss"-like hiss. For more "roar"-like hissing, like from an angry cat, see.
 * Sounds more sinister as opposed to angry compared to when used to describe a human voice.
 * Both and  appears to be common for angry swans, perhaps depending on if the sound is perceived as more cat-like or more snake-like.