Could you give annotated examples regarding the grammar of a sentence in classical Chinese where 爾 is used as an adverbial suffix?

Question

爾 here used as an adverbial suffix of classical Chinese.

Answer 1

爾/尔 in Classical Chinese can be used similarly to 然, roughly meaning "thus/so/in such a manner", changing the word to which it's suffixed into an adverb. Here's an example from Mencius 孟子 we can analyze:

一簞食，一豆羹：得之則生，弗得則死。嘑爾而與之，行道之人弗受；蹴爾而與之，乞人不屑也。

My attempt at a faithful English translation:

A basket of rice, a platter of soup: with them one survives; without them one dies. When offered insultingly, a vagabond would not accept them; when offered trampled, even a beggar would reject them.

Here we see 爾 modify the verbs 嘑 (to insult) and 蹴 (to trample) to convert them into adverbs that indicate how the food is offered.

Answer 2

Examples for 尔 used as a adverbial suffix:

莞尔，an adverb for "smile".

卓尔，an adverb for… er… "act extraordinarily".

率尔，an adverb for "act rashly, etc.".

Links above are references for the character and phrases, maybe a little elusive for non-native speakers, but you can have a glance.