When looking for synonyms for the phrase "shady lair," there are a few options that come to mind. Some people might prefer to use the phrase "shadowy den," which can suggest a more mysterious or sinister atmosphere. Others might use the phrase "dim hideout," which can convey a sense of secrecy or concealment. Still others might use the word "obscure" to describe a place that is dark or hard to see, or "hidden" to suggest that something is concealed or difficult to find. Whatever your preference, there are plenty of ways to describe a dark, shady place.