The point of the pencil has become dull. ✬

All work and no play makes Jack a dull boy. ✬

I can't write with this dull pencil. ✬

This knife is so dull that it can't cut. ✬

I have a dull ache here. ✬

My job is dull and boring. ✬

The knife was so dull that I couldn't cut the meat with it and I had to use my pocketknife. ✬

Such a person is seldom dull. ✬

Tom tried to cut the delicious-looking meat with a dull knife. ✬

The knife is dull. ✬