further underground (6)
I believe the answer is:
deeper
(Other definitions for deeper that I've seen before include "Wiser" , "Lower in pitch" , "more involved" , "More profound or more intense" , "Profounder" .)
I believe the answer is:
deeper
(Other definitions for deeper that I've seen before include "Wiser" , "Lower in pitch" , "more involved" , "More profound or more intense" , "Profounder" .)