"Adj." is typically used as an abbreviation of the word "adjective," which is a part of speech used to describe nouns or pronouns. Some synonyms for "adj." include "descriptive," "qualifying," and "modifying." Each of these words describes the general concept of an adjective, which is to provide further detail or information about a noun or pronoun. Other synonyms might include "characterizing," "embellishing," "ornamenting," or even "decorative" - though these may be used less commonly in formal writing or grammar discussions. Ultimately, all of these words describe the concept of using language to add depth and nuance to written or spoken communication.