Noun

1. A low bed on wheels that can be rolled underneath another bed.
2. A small wheel or roller.
3. The process of doing a turd (c.f. a liquid trundle).

   My mate went to the toilet to take a trundle.

Verb

1. To wheel or roll, especially by pushing.

   Every morning, the vendors trundle their carts out into the market.

2. To (cause to) roll slowly and heavily on wheels.
3. Move heavily (on wheels).