Faint means weak or barely perceptible — a faint smell, a faint hope — and as a verb, to lose consciousness. A feint is a deceptive movement, especially in boxing or fencing. The phrase is "faint praise", and "faint-hearted" takes the A.
The core difference
Weakness, and a deliberate deception.
- faint — weak, slight; to pass out: a faint faint noise, she fainted, faint-hearted.
- feint — a deceptive move: feinted left, went right.
The shared root, oddly
Both come from French feindre, to feign. Faint arrived meaning "feigned" and drifted through "cowardly" to "weak"; feint kept the deception sense. So the pair are the same word, separated by several centuries of drift.
Stationery note
Feint ruled paper — with narrow faint lines — uses the E spelling, which looks like a mistake and is not. It is a printing term, and it is the one place the spellings genuinely collide in meaning.