Definitions

1. adjective

not having a drain; especially not having a drain or pipe for the removal of liquids

“The drainless aquarium tank was designed for aquatic plants.”

2. adjective

not draining; especially not draining or losing liquid, especially water

“The drainless soil in the garden required additional irrigation.”

3. noun

a drainless area or container

“The drainless compartment in the ship was used for storing water.”