～ざるTo not ~, Un~

ざる is the attributive form of the classical auxiliary verb ず. It keeps the same negation 'not' meaning as ず, and will conjugate with verbs in the same way as ない. ざる will also often be translated as 'un~', like in 'unstoppable'.

In most cases, ざる will be seen attached to verbs that are describing a noun that comes directly after them.

Although ざる may be used in place of ない, in modern Japanese it is primarily only seen as part of common expressions or sayings, such as the ざるを得(え)ない 'have no choice but to (A)' grammar structure.

Caution

As with many old-fashioned grammar patterns, ざる will conjugate with the せ stem of する, rather than the more modern し stem.

Fun-fact

Some dictionaries list ざる as the attributive form of the classical auxiliary verb ざり. However, ざり itself is just a contraction of ず and あり 'to be'. Due to this, both variations may be considered as correct, with ず being the underlying origination.