名詞 retardation:

1. a decrease in rate of change
   同義詞：deceleration, slowing
2. the extent to which something is delayed or held back
3. any agent that retards or delays or hinders
   同義詞：retardant, retardent
4. lack of normal development of intellectual capacities
   同義詞：mental retardation, backwardness, slowness, subnormality
5. the act of slowing down or falling behind
   同義詞：slowdown, lag

1. A person of mild mental retardation having a mental age of from7 to12 years and generally having communication and social skills enabling some degree of academic or vocational education. The term belongs to a classification system no longer in use and is now considered offensive.
   癡愚者一個人智能遲緩發(fā)展，僅具有7歲到12歲的智能，一般在一定程度的學術或職業(yè)教育后能夠進行交流和掌握社會技術。這個詞是一個集合概念，現(xiàn)在不再使用，并被視為帶有侮辱意味
2. A person of profound mental retardation having a mental age below three years and generally being unable to learn connected speech or guard against common dangers. The term belongs to a classification system no longer in use and is now considered offensive.
   低智商者指智力水平在三歲小孩以下，聽不懂連貫話語，也不會提防普通危險的智力有嚴重障礙的人。這個詞現(xiàn)在已不用來區(qū)別人的類型，現(xiàn)在被認為有對人不友好的意思

re.tar.da.tion

n.（名詞）

The act or process of retarding.
阻滯，妨礙：阻礙的行為或進程
The condition of being retarded.
阻滯因素：被阻礙的條件
The extent to which something is held back or delayed.
延遲程度：某些事情被阻止或延遲所達的程度
Something that retards; a delay or hindrance.
障礙：某些阻礙物；延遲或阻礙者
Mental retardation.
智力遲鈍
Music A diminishing of tempo; a retard.
【音樂】 拍子的減慢；減速