clear as crystal
see crystal clear.
Lyrics We Totally Didn’t Get As KidsWe'll blow your mind with this list of lyrics you didn't get when you were younger—but will totally understand now.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.