Perspective is a point of view, or the technique of representing depth. Prospective means likely or expected in the future — a prospective client is one you hope to gain. One is a noun about seeing; the other is an adjective about what is coming.
The core difference
A noun about viewpoint and an adjective about the future.
- perspective (noun) — a point of view: from her perspective. Also the drawing technique.
- prospective (adjective) — expected, potential: a prospective tenant.
The roots
Both from Latin specere, to look. Per- is through — looking through, hence a viewpoint. Pro- is forward — looking ahead, hence the future sense. The prefixes carry the whole difference.
The related noun
Prospect is the noun from the second — a prospect is a possibility, or a potential customer. And in perspective means with a sense of proportion, which is a distinct idiom worth knowing.