A word that has the same or nearly the same meaning as another word. Often used in linguistic contexts.
See also: 同義語
"同意語" is also called "同義語".
This dictionary contains many synonyms.
類義語 refers to words with similar but not identical meanings, i.e., near-synonyms, whereas 同意語 can imply a closer or identical meaning.
対義語 is an antonym, the opposite of a synonym.
同意 (same meaning) + 語 (word). A straightforward compound of Sino-Japanese elements.