词根：tard = slow

  来自拉丁语的tardus意为slow。它的同义词根是slo,反义词根是来源于拉丁语celer的词根cel,celer意为swift。


同源词：

1. retard（因落后而慢re(=back) + tard(=slow)）
  vt.妨碍；拖延，推迟
  retardation n.妨碍；迟延，拖延
  Firefighters use certain chemicals that retard the spread of a fire.消防队员使用特定的化学物质阻止火势蔓延。

2. tardy
  adj.缓慢的，迟钝的；拖拉的；迟到的
  tardily adv.拖拖拉拉地，迟缓地
  tardiness n.缓慢；迟到
  tardy progress/repentance 缓慢的进展/迟来的后悔
  tardy in offering help 不情愿帮忙的
  be tardy for school上学迟到

词根：cel, celer = swift 快速

  来源于拉丁语 celer意为swift 迅速。其反义词根为slo, tard,意为slow。

同源词：

1. accelerate [使某物更快ac<ad(=to．add)+coler(=swift)]
  vt. 使加速：促进
  vi. 加快
  acceleration  n. 加速；促进
  acceierator  n. 如速者，加速嚣
  Globat warming continues to accelerate more each year. 全球变暖每年持续加速。

2. celerity [快的状态celer（=swift）]
  n. 迅速，敏捷
  Our teenage son shows amazing celerity when we call him to dinner. 我们喊我那十几岁的儿子吃晚饭时，他的反应快得惊人。

3. accelerando
  adj./adv. 渐快的（地）*ac<ad(=to)

4. decelerate
  v. 减速 *de(=down)

5. excel
  v. 胜过，优于  *ex(=out)

6. excellence
  n. 卓越，优秀；优点，长处 *ex(=out)
  prize for excellence in furniture design  家具设计优秀奖
  his excellence in all forms of sports  他在所有运动项目上的出色

7. Excellency
  n. 阁下（对大使、总督等的尊称）*ex(=out)
  Your Excellency  （直接称呼）阁下
  His／Her Excellency  （间接提到时的称呼）阁下

词根词缀：aello-

【来源及含义】Greek: stormy wind, whirlwind; from Greek mythology, Aëllo, a harpy; whose name literally means, "Stormswift"

【相关词根词缀】 Cross references of word groups that are related, directly or indirectly, to: "air, wind": aeolo-; aero-; anemo-; atmo-; austro-; flat-, flatu-; phys-; pneo-, -pnea; pneumato-; turb-; vent-; zephyro-.

【同源单词】Aello, aelophile, aelophilous, aelophily, aeolation, aeolian deposit

词根词缀：celer-

【来源及含义】Latin: fast, speed, swift, rapid

【相关描述】Compare this element with brady- for words with opposite meanings.

【同源单词】accelerant, accelerate, accelerate, accelerated, accelerated idioventricular rhythm, acceleration

词根词缀：rap-, rav-

【来源及含义】Latin: tearing away, seizing, swift, rapid; snatch away, seize, carry off; from Latin rapere, "to seize by force and to carry off"

【同源单词】correption, enrapt, enrapture, enraptured, fluviraption, nonusurping

词根词缀：tacho-, tach-, tachy-

【来源及含义】Greek: fast, speed, swift, rapid

【同源单词】acestachy, acrotach, auxetachy, bradypnea, cardiotachy, hemotachometer

词根词缀：tigri-, tigr-, tiger

【来源及含义】Greek > Latin > Old French: swift animal

【同源单词】tiger, tigress, Tigris River, tigrish, tigroid, tigrology

词根词缀：veloci-, veloc-, velo-

【来源及含义】Latin: fast, speed, swift, rapid

【同源单词】Estot velocior vita, velocimeter, velocipede, velocipedist, Velocisaurus, velocity