The adjective has 5 meanings:
Meaning #1:
clearly defined
Synonyms: defined, settled
Meaning #2:
having or given a form or shape
Antonym: unformed (meaning #1)
Meaning #3:
formed in the mind
Synonym: conceived
Meaning #4:
having taken on a definite arrangement
Meaning #5:
fully developed as by discipline or training"a fully formed literary style"




