ずには居(い)られないCannot help doing something, Cannot resist doing something

As mentioned in our ずに lesson, ず is an auxiliary verb that is not commonly used in modern Japanese, except for in set expressions. It has the equivalent role of ない, in expressing that something 'has not', or 'will not' happen. The case marking particle に is then combined with the adverbial particle は, and the negative-potential form of いる, いられない. ずにはいられない may be translated as 'cannot help doing (A)', or 'cannot resist doing (A)'.

ずにはいられない will be attached to the indeterminate form of verbs. This is the same stem form as ない uses.

Although ずにはいられない is often translated as 'cannot resist (A)', the literal meaning is simply 'cannot be without (A)'.

Caution

As the modern indeterminate form of する has several different forms, care will need to be taken when conjugating する verbs. While ない joins with し to create しない, ず will join with せ to create せず.