1
- no obj. no obj.(typically of something regarded as good) become smaller, fewer, or less; decrease（尤指好的事物）变小, 变少; 减少, 降低：
the birth rate continued to decline.
生育率继续下降。
1.1
- diminish in strength or quality; deteriorate减弱, 下降; 恶化：
her health began to decline
她的健康状况开始恶化
as adj. declining declining industries.衰退的产业。
2
- with obj. politely refuse (an invitation or offer)谢绝, 婉言拒绝：
Caroline declined the coffee.
卡罗琳推辞不喝咖啡。
2.1
- with infinitive politely refuse to do something谢绝, 拒绝：
the company declined to comment.
该公司拒绝做出评论。
3
- no obj.(especially of the sun) move downwards（尤指太阳）下沉。
3.1
- archaic bend down; droop〈古〉弯曲; 低垂。
4
- with obj.(in the grammar of Latin, Greek, and certain other languages) state the forms of (a noun, pronoun, or adjective) corresponding to cases, number, and gender（拉丁语、希腊语和某些其他语言的语法）使（名词, 代词, 形容词）变化词形。
in sing.
1- a gradual and continuous loss of strength, numbers, or quality日渐衰弱, 持续减少, 不断下降：
a serious decline in bird numbers
鸟的数量的严重持续减少
mass noun a civilization in decline.日渐衰落的文明。
1.1
- a fall in price or value（价格的）下跌, 贬值：
the decline of world coffee prices.
世界咖啡价格的下跌。
1.2
- archaic the sun's gradual setting〈古〉夕阳渐沉。
1.3
- archaic a disease in which the bodily strength gradually fails, especially tuberculosis〈古〉消耗病（尤指肺结核）。
短语
declining years
1
- the period of one's old age（人的）老年时期, 垂暮之年。
1.1
- the period leading up to the end of an enterprise or institution（企业或机构的）式微时期, 衰败期, 没落期：
the declining years of the Austro-Hungarian empire.
奥匈帝国的没落时期。
派生词
declinable
adjectivedecliner
noun词源
late Middle English: from Old French decliner, from Latin declinare 'bend down， turn aside'， from de- 'down'+clinare 'to bend'.