Structure
あまり(1) + に (2)+ Adjective
あまり(1) + に(2) + Adverb
あまり(1) + の + Noun
(1) あんまり
(2) にも
Details
Standard
About あまりに
Being the adverbial form of 余る 'excess', あまりに is a grammar structure that is used to convey an 'excessive' amount of something that caused a certain result. あまりに will almost always be used in sentences expressing some sort of surprise/shock about the degree of (A). Often, あまりに is translated simply as 'so much (A) that (B)', or 'way too much (A)'.
In the last example, we can see that あまり will be followed by の when linked to a noun. Occasionally, にも will be used instead of に. This just emphasizes the 'excess' of (A) further.
As the literal meaning of あまりに is quite close to 'excessively', it may be easier to remember this translation, rather than 'so much (A) that (B)'. Usually, 'it is excessively (A), so (B)' will cover most possible nuances.
Caution
あんまり is a colloquial variant of あまり that is often said, but should be avoided in any form of formal/official writing.
Related
Vocab Coverage
All Bunpro Vocab that appears on this item.
Examples
--:--
余りに早く着いてしまった。
I unfortunately arrived too early.
そのケーキは余りに大きすぎて、食べられない。
That cake is too big to eat.
余りに寒すぎて、帰ってきてしまった。
It was too cold, so I turned back.
その計画は余りに非現実的だよ。
That plan is too unrealistic!
余りに仕事が多すぎて、手に負えない。
I have too much work to deal with.
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あまりに and あまりにも
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あまりに – Grammar Discussion
Most Recent Replies (8 in total)

Haruka
Thank you, @mrnoone! I understand it better now. Also thanks for explaining the other use of というのも, it would have completely confused me.

notasas
Of these rules, which one applies in the following sentence?
その言い訳はあまりにも幼稚すぎる。My dictionary lists 幼稚 as a noun so shouldn’t the last rule apply? Or is -すぎる acting as -する here or something?

The111
Sad to see this question unanswered after 3 years. AFAICT, 幼稚 is a na-adjective, and adding the すぎる makes it a verb. In either case, it needs the adverbial 余りに in front.
But the sentence below does have に preceding a noun, which quite confused me.
余りに仕事が多すぎて、手に負えない。
In the absence of a real explanation anywhere, I had a long conversation with an LLM about this, and I will repeat it h...