自欺欺人【zì qī qī rén】
deceive oneself as well as others
[成]用自己都无法置信的话或手法来欺骗别人

自欺欺人的结果只会害人害己。
Self-deception can only result in hurting oneself as well as others.
自然【zì rán】
1. natural; world; nature 2. naturally 3. naturally; of course
[名]1、人类生存的物质世界 [形]2、自由发展,不经人力干预 3、表示理所当然

我喜欢呼吸大自然的新鲜空气。
I like to breathe the fresh air of nature.

她的头发自然卷曲。
Her hair curls naturally.

只要努力学习,自然能取得好成绩。
You can get a high score as long as you study hard.
自杀【zì shā】
commit suicide; lay hands on oneself; take one's own life
[动]自己杀死自己

那个老人跳河自杀,但被好心人救上岸来了。
That old man tried to kill himself by jumping into the river, but he was saved by kind people.