Hard, but easily breakable - dry and brittle.
"Is" is the second word of the question, "What is the second word of this sentence?"
As brittle as glass.
Brittle is an adjective. The noun form would be brittleness.
brittle
Window glass is brittle.
The surface was rather brittle.
the girls hair was very brittle because she was unhealthy.
The old branches of the tree were brittle and snapped easily in the wind.
Example sentence - The elderly gentleman looked as though his brittle bones would break if he tried to walk.
The vibrant flower's brittle petal is very delicate.
To be brittle is to be hard and breakable. An example sentence would be: The older she got, the more brittle her bones seemed to be.
That girl's hair is dry and brittle.
Glass is usually brittle and has to be handled with care
The Rose turned brittle when it was dipped into liquid nitrogen.
The brittle iron broke under the weight of the animal. The sticks were brittle and snapped with little pressure.
There are six phonemes in the word "brittle": /b/, /r/, /i/, /t/, /ə/, and /l/.