二者含义不同。Application是名词，意思是申请、请求、申请书、申请表、应用、运用、涂抹、敷用等。Applicant是名词，意思是申请人。
applicant例句
The job applicant must have good verbal skills.
应聘这份工作的人必须具有良好的语言表达技能。
The applicant has experience in teaching and, more relevantly,in industry.
这名申请者有教学经验，更重要的是，也有企业工作的经验。
Not every applicant had a degree.
不是所有的求职者都有学位。
application例句
Someone has mixed up all the application forms.
有人把申请表都弄乱了。
Your application will be kept on file.
你的申请书将存档。
My application got lost in the post.
我的申请书寄丢了。
Have you sent in your application yet?
你把申请书寄去了没有？