### Clue: Quicksand of sorts? (5)
### Answer: SHARP 
 ### Explanation: Definition: Quicksand of sorts
Another lift-and-separate involving quicksand, though more conventional this time: this is a double definition, with quick=sharp, as in quick-witted, and "sharp sand" is used in building etc. (You'll have to image a split in the underlining of the definitions between k and s!)