slick as a whistle
Very-smooth and neat; also, smoothly, quickly, easily. For example, That salesman is as slick as a whistle, or The fence post went in place slick as a whistle. The allusion in this simile, first recorded in 1830, is not totally clear, but presumably it refers either to the ease of producing a whistle or to its clear tone.
Words nearby slick as a whistle
slice bar, slice of the pie, slice-of-life, slicer, slick, slick as a whistle, slicken, slickenside, slicker, slickrock, slickster
The American Heritage® Idioms Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.