Definitions

1. verb

to stain or color (something) underneath, especially as an artistic technique

“The painter chose to understain the wood to create a subtle contrast.”

2. noun

the act of staining or coloring something underneath

“The understain added depth to the otherwise plain painting.”

3. adjective

relating to the act of staining or coloring something underneath

“The understain effect is often used in modern art to create a unique look.”