名詞 imperfect:

1. a tense of verbs used in describing action that is on-going
   同義詞：progressive, progressive tense, imperfect tense, continuous tense

形容詞 imperfect:

1. not perfect; defective or inadequate
2. having the attributes of man as opposed to e.g. divine beings
   同義詞：fallible, frail, weak

1. He had only an imperfect understanding of his task.
   他對自己的任務只是一知半解。
2. The quality or condition of being imperfect.
   不完美不完美的狀態(tài)或性質
3. Imperfect articles are rejected by our quality control.
   我們進行質量檢驗時，有缺陷的產(chǎn)品均予剔除。
4. We live in an imperfect society.
   我們生活在一個不完美的社會中。

im.per.fect

adj.Abbr. imp.,imperf.（形容詞）縮寫 imp.,imperf.
Not perfect.
不完美的
Grammar Of or being the tense of a verb that shows, usually in the past, an action or a condition as incomplete, continuous, or coincident with another action.
【語法】 未完成過去時的：屬于或作為動詞的一個時態(tài)的，該時態(tài)表示一個動作或狀態(tài)是未完成的、延續(xù)的或與其他動作同時發(fā)生的，通常用過去時
Botany Having either stamens or a pistil only. Used of a flower.
【植物學】 不完全的：只有雄蕊或雌蕊的。用于描述花
Law Not legally enforceable:
【法律】 在法律上不能實施的：
例句：
an imperfect contract.
不能履行的合同

n.Abbr. imp.,imperf.（名詞）縮寫 imp.,imperf.
A piece of merchandise having a minor flaw that does not impair its use, usually sold at a discount.
處理品，瑕疵品：有小缺陷但不影響其使用的商品，通常打折出售
Grammar
【語法】
The imperfect tense.
未完成式
A verb in the imperfect tense.
未完成式動詞

來源：
Middle English imparfit
中古英語 imparfit
from Old French imparfait
源自 古法語 imparfait
from Latin imperfectus
源自 拉丁語 imperfectus
in- [not] * see in-
in- [不] *參見 in-
perfectus [perfect] * see perfect
perfectus [完美的，完成時的] *參見 perfect

【引伸】
imper.fectly
adv.（副詞）
imper.fectness
n.（名詞）