I have difficulty understanding the exact difference between these two adjectives, semantically. This is quote from a native English speaker:
Parasite single? I guess an embittered parent wrote that one.
Why has the author written embittered instead of bitter? Is a different adjective used for a human and an object?
A person who is embittered was made bitter, as opposed to being transiently bitter for some reason or another. The use of embittered in this sentence suggests that the parent has a particular ax to grind with whatever institution the speaker belongs to.
Source : Link , Question Author : Persian Cat , Answer Author : Dan