なさる

なさる is the honorific (尊敬語) form of する ("to do"). It is used when describing the actions of someone you wish to show respect toward, such as a superior, a customer, or an older person. You never use it to describe your own actions.

Conjugation

なさる is a godan (五段) verb, but it has an irregular ます-form: the expected なさります becomes なさいます.

• Non-past polite: なさいます
• Past polite: なさいました
• Negative polite: なさいません
• て-form: なさって

Usage with する compound verbs

なさる can replace する in する-compound verbs (e.g. 勉強する、旅行する、運動する) to make them honorific.

～なさい – Command form

The imperative form なさい is used as a relatively soft command or instruction, often by parents or teachers speaking to children or students. This usage does not convey the same honorific nuance.

Comparison with お～になる

Another common way to form honorifics is お + V[stem] + になる (e.g. お読みになる). なさる is specifically the honorific replacement for する, while お～になる is a general pattern that works with most verbs.