noun
the same meaning; synonymous
Used to state that two words or expressions share the same meaning. Often appears in dictionary contexts or linguistic explanations.
この二つの単語は同意義です。
These two words have the same meaning.
類義 means 'similar meaning' (near-synonym), while 同意義 means 'identical meaning'.
Compound of 同 (same) + 意義 (meaning). A straightforward Sino-Japanese word.