名詞 infinitive:

1. the uninflected form of the verb

in.fin.i.tive

n.Abbr. inf.,infin.（名詞）縮寫 inf.,infin.
A verb form that functions as a substantive while retaining certain verbal characteristics, such as modification by adverbs, and that in English may be preceded byto, as in To go willingly is to show strength or We want him to work harder, or may also occur without to, as in She had them read the letter or We may finish today. See Usage Note at split infinitive
不定式：一種動詞的形式，起名詞作用而又保持了某些動詞的特征，如由副詞來修飾。在英語中，不定式由to 引導(dǎo)，比如 愿意去是為了顯示力量 或 我們希望他工作更加努力 ，也可不帶 to ，如 她讓他們看那封信 或 我們可以今天結(jié)束 參見 split infinitive

來源：
From Middle English infinitif [of an infinitive]
源自 中古英語 infinitif [不定式的]
from Old French
源自 古法語
from Late Latin onfonotovus [unlimited, indefinite, infinitive]
源自 后期拉丁語 onfonotovus [不限制，不確定，無窮的]
from Latin onfonotus [infinite] * see infinite
源自 拉丁語 onfonotus [無窮盡的] *參見 infinite