Rock and roll primarily lacking in training of singers (6)
I believe the answer is:
gneiss
'rock' is the definition.
(gneiss is a kind of rock)
I don't understand the remainder of the clue.
(Other definitions for gneiss that I've seen before include "Metamorphic rock" , "Coarse-grained rock; sounds like agreeable" .)
I've seen this clue in The Guardian.
Want a hint initially instead of a full solution?
Install my app