前人文獻中提到日語的形容詞具有「用言」與「體言」兩種用法。本文針對日語的形容詞、動詞與名詞分析並比較其範疇內容與句法功能。特別是依據〈體言性〉、〈用言性〉、〈規定性〉 (又稱為〈連體言性〉)等 3種句法語意屬性來詳細比較這三種詞類的相同性與相異性，藉以釐清日語形容詞的全貌與真相。論文的結構大致如下。第 1節「前言」，概述本文的研究目的與相關前人文獻。第 2節「形容詞與動詞的比較」，論述形容詞與動詞都具有語尾活用變化、修飾用法與述語用法等，並進一步分析兩者的共通點與相異點。其次，第 3節「形容詞與名詞的比較」，詳細分析兩者之間的相異性與共同性。接著，第 4節「形容詞、形容名詞與名詞的比較」，藉由〈體言性〉、〈用言性〉、〈規定性〉 3種「語意屬性」以及〈正〉、〈負〉、〈中間性〉 (即沒有正負值標示的中立值)等 3種「值」來詳細分析形容詞、動詞、名詞、形容名詞、動名詞與助詞等詞類的句法範疇，並試著針對這些句法範疇的句法功能予以「條理化」。最後，第 5節「結語」，總結本文內容並提出今後的研究課題。

According to the previous literature, Japanese adjectives are said to manifest both properties. The present paper, therefore, aims to examine the nominal or verbal functions manifested not only by adjectives, but also by nouns, verbs, adjectival nouns, verbal nouns and other grammatical categories, by means of syntactico-semantic feature (i.e.〈± nominal〉, 〈± verbal〉, 〈± restrictive〉) analysis. The contents of the paper are as follows. Section 1 briefly introduces the purpose and the main contents of the paper. Section 2, in turn, discusses the distinctions between adjectives and verbs, with regard to their inflectional shapes, restrictive uses and predicative uses. Then, section 3, investigates the distinctions between adjectives and nouns, pointing out their differences as well as similarities, followed by section 4, which examines how adjectives, adjectival nouns, verbal nouns and other subcategories nouns differ from each, by using three syntactico-semantic features; namely, 〈±nominal〉, 〈±verbal〉 and 〈±restrictive〉. It is discovered that Japanese adjectives, verbs and nouns do not necessarily constitute absolutely discrete grammatical categories but, rather, manifest a certain degree of continuum or fuzziness. Finally, section 5 summarizes the main contents and conclusions of the paper and suggest some topics for future study.