faint

vague, dim, indefinite, obscure, ambiguous, faint

这些形容词均含“不明确的，模糊的”之意。
vague: 多指因语言不确切，太笼统或因构思含糊、不完善而造成模糊难解。
dim: 侧重指或因光线暗淡，或因年代久远、身体欠佳等因素而产生视觉或察觉方面的困难。
indefinite: 指无明确定义或限定，重点或总体轮廓不明确。
obscure: 语气最强，指晦涩难懂。
ambiguous: 指文章或讲话中，意思可能有多种理解，令人捉摸不定。
faint: 指对某事物印象不深，或指声音微弱或希望的渺茫等。

名词 faint:

1. a spontaneous loss of consciousness caused by insufficient blood to the brain
   同义词：swoon, syncope, deliquium

动词 faint:

1. pass out from weakness, physical or emotional distress due to a loss of blood supply to the brain
   同义词：conk, swoon, pass out

形容词 faint:

1. deficient in magnitude; barely perceptible; lacking clarity or brightness or loudness etc
   同义词：weak
2. lacking clarity or distinctness
   同义词：dim, shadowy, vague, wispy
3. lacking strength or vigor
   同义词：feeble
4. weak and likely to lose consciousness
   同义词：light, swooning, light-headed, lightheaded
5. indistinctly understood or felt or perceived
6. lacking conviction or boldness or courage
   同义词：fainthearted, timid, faint-hearted

1. A young student fainted in the hot sun.
   有个年幼的学生在炎炎烈日下晕倒了。
2. I heard a faint sound in the distance.
   我听到远处有个微弱的声音。
3. Our chances of victory are very faint now.
   现在我们取胜的机会已经微乎其微了。

faint

adj.（形容词）
faint.er,faint.est
Lacking strength or vigor; feeble.
衰弱的：缺乏力气或活力的；衰弱的
Lacking conviction, boldness, or courage; timid.
缺乏勇气的；胆怯的

Lacking brightness:
黯淡的：缺乏亮度的：
例句：
a faint light in the gloom.
阴暗里微弱的灯光

Lacking clarity or distinctness:
模糊的：缺乏清晰度的：
例句：
a faint recollection.
模糊的记忆

Likely to fall into a faint; dizzy and weak:
昏晕似的；虚弱的：
例句：
felt faint for a moment.
忽然晕倒了

n.（名词）
An abrupt, usually brief loss of consciousness, generally associated with failure of normal blood circulation.See Synonyms at blackout
昏厥：突然的、短暂的丧失知觉，通常跟正常血液循环减慢有关参见 blackout
v.intr.（不及物动词）
faint.ed,faint.ing,faints
To fall into a usually brief state of unconsciousness.
昏厥：进入短暂失去知觉状态
Archaic To weaken in purpose or spirit.
【古语】 丧失勇气或决心

来源：
Middle English [deceitful, cowardly]
中古英语 [欺诈的，胆小的]
from Old French [past participle of] feindre [to feign] * see feign
源自 古法语 [] feindre的过去分词 [假装] *参见 feign

【引伸】
faint.er
n.（名词）
faint.ly
adv.（副词）
faint.ness
n.（名词）