vi.

1. 下降，下跌；减少；衰退，衰落
   As one grows older one's memory declines.

   人的记忆力随着年龄增长而衰退。

   Unemployment declined to 4 percent last month.

   上个月失业率降至百分之四。

2. 【书】倾斜；下垂
3. 婉拒；谢绝

vt.

1. 婉拒；谢绝[+to-v]
   She declined their invitation.

   她婉拒了他们的邀请。

   She declined to have lunch with her friend, saying that she wasn't feeling well.

   她说她身体不舒服，婉拒了与她的朋友共进午餐。

2. 【语】使发生词尾变化，使变格

n.

1. 下降；减少[S1]
   There is a decline in real wages.

   实际工资有所减少。

2. 衰退，衰落[the S]
3. 最后部分；晚年[the S]
4. 倾斜[the S]

v.

1. become smaller, fewer, or less; decrease.
   ▸diminish in strength or quality; deteriorate.
2. politely refuse:
   the company declined to comment.
3. (especially of the sun) move downwards.
4. Grammar  state the forms of (a noun, pronoun, or adjective) corresponding to cases, number, and gender.

n.

1. a continuous loss of strength, numbers, or value.
2. archaic a disease in which the bodily strength gradually fails, especially tuberculosis.