一層(いっそう)

いっそう
adverb
more, all the more, further
See also: 一掃(いっそう) (clean sweep (一掃))
1. more, all the more, even more
To an even greater degree than before.
一層(いっそう)努力(どりょく)します。
I'll try even harder.
雨(あめ)で一層(いっそう)寒(さむ)くなった。
The rain made it even colder.
夜(よる)になると一層(いっそう)静(しず)かになる。
It becomes even quieter at night.
問題(もんだい)は一層(いっそう)複雑(ふくざつ)になって、なかなか解決(かいけつ)できなくなった。
The problem became even more complicated and became hard to solve.
この経験(けいけん)のおかげで彼(かれ)は一層(いっそう)自信(じしん)を持(も)つようになり、仕事(しごと)にも積極的(せっきょくてき)に取(と)り組(く)んでいる。
Thanks to this experience, he became even more confident and is now actively engaged in his work.
2. further, still more
An additional degree or extent.
一層(いっそう)の注意(ちゅうい)が必要(ひつよう)だ。
Further caution is required.
一層(いっそう)の + noun pattern
一層(いっそう)の発展(はってん)を願(ねが)います。
I wish for further development.
一層(いっそう)のご協力(きょうりょく)をお願(ねが)いします。
We ask for your further cooperation.
練習(れんしゅう)を重(かさ)ねて一層(いっそう)の上達(じょうたつ)を目指(めざ)している。
I'm building up practice and aiming for further improvement.
今回(こんかい)の失敗(しっぱい)を教訓(きょうくん)にして、一層(いっそう)の努力(どりょく)を重(かさ)ねていきたいと思(おも)います。
I want to learn from this failure and continue to make further efforts.

一層(いっそう) means "all the more" or "even more," emphasizing an increase in degree. More formal than もっと.

PATTERNS:

  • 一層(いっそう) + adjective/verb: 一層(いっそう)難(むずか)しくなった (became even more difficult)
  • 一層(いっそう)の + noun: 一層(いっそう)の努力(どりょく) (further effort)

SIMILAR WORDS (increasing formality):

  • もっと: more (casual, everyday)
  • さらに: furthermore, additionally (neutral-formal)
  • 一層(いっそう): all the more (formal, emphatic)
  • 一段(いちだん)と: even more (formal, written)

CAUTION:
Do not confuse with 一掃(いっそう) (clean sweep, eradication), which is a different word with the same pronunciation.

REGISTER:
Formal. Common in written language, speeches, and business communication.

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Added 2026.1.9 20:57 · Revised 2026.3.27 4:36
01500/01730_issou