なしに and なくして both mean “without.” They act as formal, written adverbial phrases meaning “without doing [A]” or “without [A].” Grammatically, they are the formal equivalents of casual phrases like 〜しないで, 〜せずに, or 〜なしで.
While they are virtually interchangeable, なくして is significantly more formal, literary, and profound. You will typically only see it in literature, newspapers, or philosophical statements.
Warning: Do not confuse なくして with the verb 失くす (to lose). This grammar point is actually derived from the classical literary te-form of ない (無い ➔ 無くして), meaning “non-existent” or “without.”
Connection Rules: Nouns vs. Verbs
Whether you are using なしに or なくして, the connection rules are exactly the same. Nouns connect directly to the grammar point. Verbs cannot connect directly; you must use the dictionary form and nominalize it by attaching こと.
【Noun】 + なしに / なくして
【Verb: Dictionary】 + ことなしに / ことなくして
Usage 1: Without doing… (なしに / なくして)
In its base form, this grammar point simply describes an action taken without something else happening or being present.
価格は予告なしに変更することがあります。
Prices are subject to change without prior notice.
社長の出席なしに会議を開始する。
Start the meeting without the CEO present.
誰も傷つくことなしに、問題が解決した。
The problem was resolved without anyone getting hurt.
愛なくして何が人生だろうか。
Without love, what is life?
Usage 2: Absolute Condition (なしには / なくしては)
When used with the topic particle は, the nuance shifts to an absolute condition: “If not for [A], [B] is impossible.”
Crucial JLPT Rule: Because it forms an absolute condition, when you use なしには or なくしては, the second half of the sentence must always end in a negative outcome or describe an impossible state.
彼の許可なしには入場することができない。
You cannot enter without his permission.
政党は、投票者の懸念を考究することなしには存在できない。
A political party cannot exist without considering the concerns of the voters.
苦労なくしては利益はない。
No pain, no gain. (Literally: Without hardship, there is no profit.)
努力することなくして、成功はあり得ない。
Without making an effort, success is impossible.
涙なくしては見られない映画。
A film you can’t watch without crying. (Note: なしには can also be used here).