なさる is a 尊敬語(そんけいご) (honorific speech) verb which acknowledges and respects the actions of another (never the speaker). Like
お~になる,
なさる has exactly the same meaning as
する.
なさる can be utilized in any situation where
する would be used, as a direct replacement. It is a special-class verb, which means that it has some unique conjugation rules. In its casual form, it will conjugate in exactly the same way as a
う-Verb.
-
週末(しゅうまつ)もお仕事(しごと)をなさるのですか。
Are you going to work over the weekend also?
-
勘違(かんちが)いなさらないで下さい。
Please don't take this the wrong way.
-
社長(しゃちょう)は先週(せんしゅう)どちらでゴルフをなさったのですか。
Boss, where did you go to play golf last week?
-
納得(なっとく)なさらないなら私(わたし)に言(い)ってください。
If you are not with me on this, please let me know.
However, in the polite form, instead of る changing to り (as would be expected of a
う-Verb), it will change to い instead.
-
お飲(の)み物(もの)はどうなさいますか?
What would you like to drink?
-
忘(わす)れ物(もの)はなさいませんか。
Did you forget anything?
-
お客様(きゃくさま)、どうなさいましたか。
Valued guest, what seems to be the issue?
-
彼(かれ)は計画(けいかく)を変(か)えることはなさいませんでした。
He did not do anything to change the plan.
Although some Japanese speakers will use it, expressions like
なさっていらっしゃる are considered double keigo (
なさる is 尊敬語(そんけいご), and
いらっしゃる is also 尊敬語(そんけいご)), and are technically incorrect. However,
なさる may be partnered with ます, which is simply 丁寧語(ていねいご) (polite speech).
-
社長(しゃちょう)は今(いま)、ゴルフをなさっていらっしゃる。
The CEO is currently playing golf quite playingly. (Unnatural Japanese, with unnatural English to match!)
-
社長(しゃちょう)は今(いま)ゴルフをなさっています。
The CEO is currently playing golf. (Natural Japanese)
なさる is considered a little bit old fashioned in modern Japanese, and お~になる is the preferred form used by most native speakers.