expression
Irregular -te form of the honorific verb なさる. Used in respectful requests or continuative constructions, e.g. ご覧なすって or お待ちなすって. Not a standalone word; always part of a verb phrase.
See also: なさる
どうぞご覧なすってください。
Please have a look (honorific).
少々お待ちなすってくださいませ。
Please wait a moment (honorific).