difficult to see, hear, smell etc

不清楚的，模糊的:

She gave a faint smile.

她淡淡一笑。

a very faint noise

很微弱的声响

the faint light of dawn

微弱的晨曦

a faint hope / possibility / chance etc, a very small or slight hope etc

很小的希望/可能性/机会等:

a faint hope that they might be alive

他们渺茫的生还希望

not have the faintest idea to not know anything at all about something

完全不知道:

I don't have the faintest idea what you're talking about.

我一点都不知道你在说什么。

feeling weak and as if you are about to become unconscious because you are very ill, tired, or hungry

〔因生病、疲倦或饥饿而〕虚弱的:

The heat made him feel quite faint.

高温令他感觉很虚弱。

I was faint with hunger.

我饿昏了。

Everyone looked faintly surprised.

所有人看上去都有点吃惊。

The sun shone faintly through the clouds.

微弱的阳光透过云层照射下来。

to suddenly become unconscious for a short time

晕倒，昏厥;

Several fans fainted in the blazing heat.

几个球迷在炽热高温下晕过去了。

I nearly / almost fainted, [spoken] used to say that you were very surprised by something

我差点昏过去〔表示很惊讶〕:

I nearly fainted when they told me the price.

他们告诉我价格时，我差点昏过去。

an act of becoming unconscious

昏厥:

She fell down in a faint.

她昏倒了。