さらに・更にsarani[1]atamadaka (head-high)

1. adverb, conjunctionfurthermore; again; after all; more and more; moreover; even more
   これでさらに困こまったことになるだろう。↗

   This will add to our troubles.

• SynonymなおWrittenWritten/formal prose. Covers 'still' and 'even more', and as a conjunction adds an item, as in 「尚、詳細は…」; typical of official documents.
• SynonymまたNeutralNeutral. Means 'again' or 'also', as in 「また来る」; centers on repetition, while 「更に」 centers on stepping up in degree.
• SynonymなおかつWrittenWritten/formal prose conjunction meaning 'moreover, and', stressing that both qualities hold, as in 「安く、なおかつ美味しい」.
• Synonymその上そのうえNeutralNeutral conjunction meaning 'moreover, on top of that', as in 「安い、その上丈夫だ」; adds items in parallel but does not express rising degree.
• Synonym一層いっそうNeutralNeutral. Means 'even more', as in 「一層寒くなった」; only raises degree and cannot serve as a conjunction to add items.
• SynonymそれにCasualColloquial conjunction meaning 'besides, and', as in 「疲れたし、それに眠い」; used to add a reason.
• Synonymこの上このうえNeutralNeutral. Means 'on top of this', as in 「この上何を望むのか」; often carries the nuance that things are already enough.
• SynonymなおもWrittenWritten/formal prose. Means 'still, continuing', as in 「尚も抵抗を続ける」; stresses continuation, while 「更に」 stresses rising degree or added items.
• SynonymなおまたWrittenWritten/formal prose conjunction meaning 'besides, moreover', for adding an item; found in letters and official documents — in speech people say 「それから」 or 「あと」.
• Synonymそれ以上それいじょうNeutralNeutral. Means 'beyond that degree', as in 「それ以上言うな」; often followed by a negative, close to 「更に」's sense of going further.
• Synonymかてて加えてかててくわえてWrittenWritten/formal prose idiom meaning 'to make matters worse', used when bad things pile up.
• Synonym加えてくわえてNeutralNeutral conjunction meaning 'in addition', as in 「雨、加えて風も強い」; adds an item and leans slightly written.
• Synonymなお一層なおいっそうWrittenWritten/formal prose. Means 'even further than now', as in 「なお一層努力します」; typical of solemn, formal statements.
• Synonym付け加えるとつけくわえるとNeutralNeutral. Means 'to add one more thing', used when appending an explanation while speaking; fine in both speech and writing.
• RelatedもっとCasualColloquial. Means 'more, a bit more', as in 「もっと食べたい」; more casual than 「更に」 and common in wishes and requests.
• Related再びふたたびWrittenWritten/formal prose. Means 'once again', as in 「再び訪れる」; centers on something happening a second time.
• Related改めてあらためてNeutralNeutral. Means 'anew' or 'at another time', or noticing anew, as in 「改めて感謝する」; centers on doing something over.
• RelatedまたまたCasualColloquial. Means 'yet again', often with exasperation or surprise, as in 「またまた失敗」; centers on repetition.
• RelatedまたしてもNeutralNeutral. Means 'yet again', often for unwelcome events repeating, as in 「またしても負けた」; carries a tone of regret.
• Related重ねてかさねてWrittenWritten/formal prose. Means 'once more', used to repeat a request or apology formally, as in 「重ねてお詫び申し上げます」.
• RelatedまたもやWrittenWritten/formal prose. Means 'yet again' with surprise or a sigh, as in 「またもや事故」; common in news reports.
• RelatedまたもWrittenWritten/formal prose. An emphatic form of 「また」 meaning 'once again'; common in reports and articles.

Default to 「更に」 when degree deepens or an item is added. In speech prefer 「もっと」; for degree alone use 「一層」; to add an item use 「その上」 or 「それに」; for repetition use 「また」 or 「再び」. Written alternatives like 「尚」, 「尚も」, 「なお一層」 and 「重ねて」 fit formal prose, while 「又々」, 「又しても」 and 「又も」 stress that something happens yet again.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 程度ていどなどがそれまでも強つよかったが、より増ます様さま。
2. 同おなじことが重かさなったり新あらたに何なんかが加くわわったりする様さま。
3. （後あとに打消うちけしの語ごを伴ともなって）全まったく。少すこしも。