This expression began with the literal act of pushing a wheel with your shoulder, then became a figurative way to mean hard work.

“Clean as a whistle” usually means very clean. It may also mean clear or smooth, probably from the idea of a pure whistle sound.

Canoe reached English through Spanish canoa, which was borrowed from an Indigenous Caribbean language, probably Taíno.

The phrase comes from judging a horse’s age by its teeth. Today it means you should not criticize or question a gift.