When it comes to describing a featureless mind, there are several synonyms that can be used. For instance, one might describe an unremarkable or nondescript mind, characterized by a lack of distinguishing features or traits. Alternatively, one might describe a blank or empty mind, which lacks any significant thoughts or emotions. Another possible synonym is a dull or uninteresting mind, which fails to capture one's attention or stimulate their curiosity. Other synonyms might include vacuous, vapid, or insipid, which all suggest a lack of depth or substance. Ultimately, the choice of synonym will depend on the specific nuances one wishes to convey about the state of mind in question.