improper

形容词 improper:

1. not suitable or right or appropriate
2. not conforming to legality, moral law, or social convention
   同义词：unconventional, unlawful
3. not appropriate for a purpose or occasion
   同义词：unsuitable, wrong

1. The machine tool went out of control because of improper use.
   由于使用不当，机床失去控制。
2. Improper, unlawful, or incorrect use; misapplication.
   错用不正确，不合法或错误的使用; 误用
3. You will make a mistake by using the improper tool.
   你用那种不恰当的工具会犯错误。
4. Laughing and joking are considered improper behaviors at a funeral.
   在葬礼上发笑或开玩笑是失礼的行为。

im.prop.er

adj.（形容词）
Not suited to circumstances or needs; unsuitable:
不适当的，不妥当的：和情形或需要不相称的；不合适的：
例句：
improper shoes for a walk on the beach; improper medical treatment.
不适于在海滩上散步的鞋；不适当的治疗

Not in keeping with conventional mores; indecorous:
不合宜的：和传统的规范不相符的；不体面的：
例句：
improper behavior.
不合宜的行为

Not consistent with established truth, fact, or rule; incorrect.
错误的，不正确的：与既定真相、事实或原则不一致的；错误的
Irregular or abnormal.
不规范的，不正常的

【引伸】
improp.erly
adv.（副词）
improp.erness
n.（名词）
<参考词汇><同义词>improper,unbecoming,unseemly,indelicate,indecent,indecorousThese adjectives mean not in keeping with accepted standards of what is right or proper.
这些形容词的意思是和被接受的正确或合适的标准不符的。
Improper often refers to unethical conduct,a breach of etiquette, or morally offensive behavior:
Improper 经常是指不道德的行为，对礼仪的怠慢或者无礼的举止：
例句：
pleasant but slightly improper to dine alone with a married person.
和已婚的人一起吃饭是令人感到愉快的但却稍微不合宜。

Unbecoming suggests what is beneath the standard implied by one`s character or position:
Unbecoming 意味着在某人的身份或地位所示的标准以下的：
例句：
language unbecoming to a gentleman. What isunseemly or indelicate is in gross violation of good taste;
和绅士身份不符的言语。 Unseemly 或者 indelicate 是指对良好品味的粗俗破坏：

indelicate especially suggests immodesty, coarseness, or tactlessness:
indelicate 尤指错误地使用亵渎语；
例句：
unseemly to use profanity;
不雅的暗示；

例句：
an indelicate suggestion.
失礼的提议。

Indecent refers to what is morally offensive or harmful:
Indecent 用于道德上无礼的或有害的事：
例句：
an earthy but not indecent story.
一个庸俗但并不下流的故事：

Indecorous implies violation of the mores or manners of polite society:
Indecorous 是指对文明社会的规范和礼仪的破坏：
例句：
indecorous behavior;
不合礼节的行为；

例句：
an indecorous proposition.
不道德的要求