Possible Clues:

• Ambiguous
• Nuclear output up in the air
• Uncle Arthur's day off? It isn't apparent
• Relation with a right to be less than explicit
• Not easy to see or understand
• Relatively (but not obviously) he gets the artist up
• Not obvious, obscure
• Opaque
• Relative harm after undressing in the dark
• Dim male relative content to leave alligator