Self has 8 different meanings across 4 categories:
Noun · Adjective · Pron · Proper Noun
One individual's personality, character, demeanor, or disposition.
"After years of living abroad, she realized that her self had changed more than anyone else around her could understand."
In plain English: The self is who you are as an individual, including your thoughts, feelings, and personality.
"He always acts in his own self-interest without considering others."
To fertilise by the same individual; to self-fertilise or self-pollinate.
"The botanist noted that some wild orchids have evolved a unique mechanism to ensure they can self when cross-pollination fails due to isolation."
In plain English: To self means to do something for yourself without needing help from anyone else.
"The old computer program will self-destruct if you do not enter the code within five minutes."
(used as a combining form) relating to--of or by or to or from or for--the self
"self-knowledge"
"self-proclaimed"
"self-induced"
Having its own or a single nature or character throughout, as in colour, composition, etc., without addition or change; of the same kind; unmixed.
"The self-contained studio apartment features walls painted in a completely pure white that remains unstained and unblemished from floor to ceiling."
In plain English: Self describes something that belongs to or is done by you personally rather than anyone else.
"The self-confident speaker felt ready for the interview."
Usage: Use self to describe substances like light or paint that are pure and unadulterated by foreign elements (e.g., "pure self" is incorrect; use "a self-luminous glow"). This poetic, slightly archaic adjective rarely appears in modern speech outside of fixed phrases describing color or composition.
Himself, herself, itself, themselves; that specific (person mentioned).
"The manager told himself to stay calm before addressing the angry customer."
A surname.
"The family gathered for dinner, and Mr. Self introduced his new neighbor to everyone at the table."
The word "self" comes from Old English, where it originally meant the same thing as it does today. It traveled into modern English through Middle English without changing its core meaning.