Past & Present Participles as Adjectives

Here's a clue: -ed and -ing are also stuck onto verbs, and they connote when or how the action takes place. Adding '-ed' makes a lot of verbs past tense, and it also creates the participle for perfect tenses: walk, walked, have walked. What you end up with is a sense of completed action. So, an adjective ending in '-ed' is really a participle used as an adjective, and it, too, implies complete

In addition to what Nestor said, with most verbs, -ing and -ed adjectives show whether the noun is the agent or receiver of the action expressed by the participle, which means they show two completely different situations.
"A frightening animal" is very different from "a frightened animal". Yet, neither is more 'complete' than the other. They are just different.

"A frightening an

Miriam-

That's a much better answer. It's obvious that you're the professional and I'm the amateur.

But...I stand by my assertion that one component of the difference between present and past participle adjectives is the 'completeness' of the action.

I just find it hard to use the agent or receiver rule to explain "a good-looking man" because the man is being looked rather than looking at others in this case.

When the verb base ("look" in this case) is intransitive, the -ed form won't make sense.

There's no such thing as "The man is looked good", so there is no "good-looked man".
There is, however, "The man looks good", so there is a "good-looking man".

The same would happen for other intransitives like "sleep": "a sleeping man", but not "a slept man".

Probably the