Tintinnabular is a unique and uncommon word meaning "having the sound of ringing bells." However, if you're searching for a synonym of tintinnabular to add variety to your writing, there are a few options. One possible substitute is "clanging," which can also refer to a metallic, bell-like sound. Alternatively, you could use "pealing," "jingling," or "ringing," all of which evoke the sound of bells or chimes. For a more abstract synonym, you might use "resonant," which suggests a sound that seems to reverberate or fill a space. Regardless of your chosen synonym, it's important to convey the sense of sound and clarity that tintinnabulation implies.