Transsexualism is a severe gender dysphoria, for which transsexual operation is an important therapy.是什么意思？

Transsexualism is a severe gender dysphoria, for which transsexual operation is an important therapy.

易性病是一种心理障碍性疾病, 变性手术是易性病的重要治疗方法.

is

vt.& vi. 是（be的三单形式；n. 存在；

例句
Bollinger 'RD' is a rare, highly prized wine.
博林格RD香槟是一种名贵的备受推崇的葡萄酒。

severe

adj. 严峻的，严厉的，剧烈的，苛刻的；

例句
He had severe abrasions to his right cheek.
他的右脸颊有严重的擦伤。

gender

n. <语>性某些语言的（阳性、阴性和中性，不同的性有不同的词尾等），性别，某些语言的（名词、代词和形容词）性的区分；

例句
It is not a person's gender that fits them to be a vicar but what is in their hearts.
一个人是否胜任教区牧师一职取决于其品德而不是其性别。

dysphoria

n. 病理性心境恶劣，烦躁不安，躁动，烦满，躁扰；

例句
Results The patients'pain and dysphoria were alleviated and set up correct understanding about the disease.
结果疼痛减轻,心理焦虑减轻,建立了对疾病正确的认识.

for

prep. 为，为了，倾向于，关于，当作；conj. 因为，由于；

例句
I've come looking for a bit of advice.
我特来讨教。

which

pron. 哪一个，哪一些，哪个，那，指前面提到的事物；adj. 哪一个，哪一些；

例句
...the latest date at which a foetus can be aborted.
能够打胎的最迟日期

transsexual

--

例句
Transsexualism is a severe gender dysphoria, for which transsexual operation is an important therapy.
易性病是一种心理障碍性疾病, 变性手术是易性病的重要治疗方法.

operation

n. 操作，经营，手术，[数]运算，作用；

例句
...the operation a patient has had.
病人做过的手术

an

art. 一（在元音字母前代替不定代词a），一任一某一，一个；

例句
He started eating an apple...
他开始吃苹果。

important

adj. 重要的，权威的，有势力的，有地位的；

例句
The presence or absence of clouds can have an important impact on heat transfer...
有无云层对热量的传递会产生重要的影响。

therapy

n. 治疗，疗法，疗效，心理治疗，治疗力；

例句
Physical therapy is an important adjunct to drug treatments...
物理疗法是戒毒治疗中的一种重要辅助性疗法。