Here's 汉典's rendition of 𫘏: 𫘏 according to 四川方言词语考释 dictionary means 板着(脸). 字海 【字海】 该字暂无解释！希望有识之士提供！ ("This character doesn't have an explanation yet! We hope someone who knows to add ...
□ is the offical place-marker for unknown or unwritable characters. Sometimes though there are appropriate characters for the mistakenly believed unwritable or nonexistent. Here's my conundrum: ...