0 Old HSK word(s):
难以启齿* *

Definitions from Unihan Copyright © 1991-2015 Unicode® Inc. All rights reserved.

难 difficult, arduous, hard / unable
以 by means of / thereby, therefore / consider as / in order to
启 open / begin, commence / explain
齿 teeth / gears, cogs / age / simplified form of the KangXi radical number 211
Hsk Characters:
HSK -Characters and beyond:
GbBig5EngRadMegaTripleMultilingual