The Prefix "Iz-"
The Croatian prefix iz- fundamentally means "out" or "out of." When added to verbs, it emphasizes that an action is carried through to its absolute completion. Often, this implies a sense of physical exhaustion, running out of a resource, or extracting/creating something from scratch.
Note on spelling: When iz- attaches to a root starting with an unvoiced consonant (such as k, p, or c), the z changes to an s for easier pronunciation, making the prefix is-.
Bringing Things to an End (or a Beginning)
You will frequently see this prefix used when a resource or person is consumed entirely by fire or stress. Conversely, it is also used when an idea or story is pulled entirely "out" of one's head into existence.
Depleting Resources
Because it conveys absolute completion, this prefix is perfect for talking about utilizing opportunities completely, exhausting your physical strength, or extracting every last drop of a liquid. Notice how iz- becomes is- in these verbs.
Absolute Thoroughness
Finally, the prefix turns regular actions into thorough, extreme, or irreversible events. This applies to physical actions like deleting data or a timer running out, but also to intense emotional states—like driving someone completely mad or crying until you have no tears left.