The word trumpetlike implies the sound or shape of a trumpet. Antonyms for trumpetlike could include soft, quiet, gentle, muffled, or muted, as these words suggest a lack of volume or intensity. Other antonyms could be different shapes or types of sounds, for example, a whisper, groan, murmur, or rustle. The opposite of trumpetlike might also be described with adjectives related to a different sense, such as smooth, sleek, or graceful, indicating a contrast in form or texture. Hence, there are several antonyms for the word trumpetlike that could be used, depending on the context and intended meaning.